Physics Midterm Exam Directions: It Is Important To Pray

Physics Midterm Exam directions: it Is Important That You Provide Answer

Use at least two to three completed content related sentences to explain why physics is considered the basic science. Provide at least one example to explain how physics relates to other sciences.

You do work on something when you lift it against gravity. Explain how work relates to gravitational potential energy using at least two complete content related sentences. If the lifted object is released, describe the change in energy. Define all terms used in both questions.

In terms of momentum change, explain why it is best to “give” when catching a baseball. Provide at least two other examples of situations in which you want “give”.

A boy fires a table tennis launcher. Briefly describe the forces and impulses on the launcher and the ball. Explain which has momentum and which is moving faster. Use at least three to four complete content related sentences.

Write four to five sentences about what Chapter 1 says about the early scientists from Aristotle to Galileo thought about the nature of motion, including Aristotle, Galileo, and Copernicus.

Suppose you are on an airplane moving at high speed. If you flip a coin straight up, it will land in your lap rather than a great distance behind you. Explain why this is true and include any laws that help prove your point. Your answer should be at least three to four complete content related sentences.

What is terminal speed? When a skydiver has reached terminal speed, what is the air resistance equal to? What is the skydiver’s acceleration? Use at least three to four complete content related sentences.

A force is a push or a pull. Newton’s third law further defines the meaning of force. Explain using at least three to four complete content related sentences.

The sun radiates about 3.6 x 10^26 joules of energy each second. How much mass does it lose each second? Show all your work and explain all numbers used in your calculations.

Provide the time dilation equation found in Section 15.4 of the text. Explain each step of the derivation.

You sit at the outer rim of a Ferris Wheel that rotates 2 revolutions per minute (RPM). What would your rotational speed be if you were instead clinging to a position halfway from the center to the outer rim? Include at least 3 to 4 complete content related sentences and show any necessary work to support your answer.

At the outer edge of a rotating space habitat, 130 m from the center, the rotational acceleration is g. What is the rotational acceleration at a distance of 65 m from the center? Show all work and steps to support your answer.

A car traveling at 60 km/h will skid 30 m when its brakes are locked. If the same car is traveling at 180 km/h, what will be the skidding distance? Show all work to support your answer.

At what height does a 1000-kg mass have a potential energy of 1 J relative to the ground? Show all work to support your answer.

A bicycle travels 15 km in 30 minutes. What is its average speed? Show all work to support your answer.

What is the average acceleration of a car that goes from rest to 60 km/h in 8 seconds? Show all work to support your answer.

What speed must you toss a ball straight up so it takes 4 seconds to return to you? Show all work to support your answer.

Assume that a 15-kg ball moving at 8 m/s strikes a wall perpendicularly and rebounds elastically at the same speed. What is the impulse given to the wall? Show all work to support your answer.

A net force of 1.0 N acts on a 4.0-kg object, initially at rest, for 4.0 seconds. What is the distance the object moves during this time? Show all work to support your answer.

What is the energy equivalent of 5.0 kg of mass? Show all work to support your answer.

A skydiver steps from a high-flying helicopter. If there were no air resistance, how fast would she be falling at the end of a 12-second jump?

Kerry Klutz drops her physics book off her aunt’s high-rise balcony. It hits the ground below 1.5 seconds later. a. With what speed does it hit? b. How high is the balcony (ignore air drag)?

Mark accidentally falls out of a helicopter traveling at 15 m/s. He plunges into a swimming pool 2 seconds later. Assuming no air resistance, what was the horizontal distance between Mark and the swimming pool when he fell from the helicopter?

Consider the two forces acting on a person who stands still: the downward pull of gravity and the upward support of the floor. Are these forces equal and opposite? Do they constitute an action-reaction pair? Why or why not?

If a car traveling at 60 km/h will skid 20 m when its brakes lock, how far will it skid at 120 km/h when brakes lock? Show all work to support your answer.

Stand with your heels and back to the wall and lean over to touch your toes. What happens? Which would help you in completing this task, stronger legs or longer feet? Use 2 to 3 complete content related sentences to defend your answer.

Alec says the force of gravity is stronger on a piece of paper after it’s crumpled. His classmate, Jordan, disagrees. Alec proves his point by dropping two pieces of paper, one crumpled and the other not. Has Alec proven his point? Use at least 2 to 3 complete content related sentences to explain.

Calculate the speed in m/s at which the moon revolves around the Earth. Use at least 3 to 4 complete content related sentences to describe your process.

Using at least 3 to 4 complete content related sentences, describe the first and second postulate of special relativity.

You are playing catch with a friend in a moving train. When you toss the ball in the direction the train is moving, how does the speed of the ball appear to an observer standing outside the train? Use at least 3 complete content related sentences to explain.

Paper For Above instruction

Physics is considered the basic science because it explains the fundamental principles that underpin the other natural sciences, such as chemistry and biology. Physics provides the foundational understanding of matter, energy, space, and time, which are essential for comprehending the behavior of all physical systems. For example, the laws of thermodynamics in physics help explain chemical reactions, illustrating the interconnectedness of sciences. Physics's emphasis on quantitative measurement and experimentation also makes it the cornerstone of scientific inquiry, enabling advancements in technology and applied sciences.

Work is done when you lift an object against gravity because you exert a force over a distance in the direction of that force. This work increases the gravitational potential energy of the object, which is the stored energy due to its position relative to Earth. When the lifted object is released, gravitational potential energy converts into kinetic energy as the object accelerates downward, illustrating energy conservation. Definitions: work is force applied over a distance; gravitational potential energy is the energy stored due to an object’s height in a gravitational field.

In terms of momentum change, it is best to “give” when catching a baseball to reduce the force exerted on your hands and arms, minimizing injury. By giving, or increasing the time over which the momentum changes, the force experienced decreases according to the impulse-momentum theorem. Other situations where “give” is beneficial include catching a falling object to lessen impact injury and absorbing impact when stopping a moving vehicle or bicycle.

A boy fires a table tennis launcher: the forces involved include the force exerted by the launcher on the ball and the reaction force exerted by the ball on the launcher, per Newton’s third law. Impulse is the change in momentum experienced by both the ball and the launcher, and it is equal and opposite for the two objects. The ball gains momentum and moves faster than the launcher, which has less momentum and moves very little, if at all, because it’s anchored or its mass dominates. The ball’s rapid motion indicates it has more momentum and a higher speed immediately after being launched.

Early scientists revolutionized the understanding of motion. Aristotle believed that objects naturally sought their natural place and that a force was needed to keep objects moving, although he misunderstood the nature of motion. Galileo challenged Aristotle by proposing that objects maintain their motion unless acted upon by an external force, laying the groundwork for Newtonian physics. Copernicus revolutionized astronomy by suggesting that the Sun, not Earth, is at the center of the solar system, shifting the view of planetary motion and leading to the heliocentric model.

When you flip a coin on a high-speed airplane, the coin appears to land in your lap due to your forward motion being the same as the airplane’s, according to Newton’s first law of inertia. Because you and the coin share the same velocity, and no horizontal force acts on the coin during its brief ascent and descent, the coin retains your velocity and lands back in your hand. This demonstrates the principle that an object moving in uniform motion stays in that motion unless acted upon by an external force, illustrating the concept of relative motion and inertia.

Terminal speed is the maximum speed a falling object reaches when the force of air resistance equals the force of gravity. At terminal speed, the net force on the object is zero because the upward air resistance balances the downward gravitational force. As a result, the object stops accelerating and continues to fall at a constant speed. For a skydiver at terminal speed, the acceleration is zero, since the forces are balanced, and the velocity remains constant.

Force is a push or pull on an object, capable of changing its motion. Newton’s third law states that for every action, there is an equal and opposite reaction, meaning that forces always act in pairs. These action-reaction pairs occur simultaneously and on different objects, describing how forces between interacting bodies are equal in magnitude but opposite in direction. This law explains phenomena like the thrust of a rocket and the recoil of a gun.

The sun radiates about 3.6 × 10^26 joules each second. Using Einstein’s mass-energy equivalence equation, E=mc^2, rearranged to m=E/c^2, the mass lost each second is m = 3.6 × 10^26 J / (3 × 10^8 m/s)^2. Calculating this: m ≈ 3.6 × 10^26 / 9 × 10^16 ≈ 4 × 10^9 kg. Therefore, the sun loses approximately 4 billion kilograms of mass every second due to energy radiation.

The time dilation equation in special relativity is t' = t / √(1 - v^2/c^2), where t' is the dilated time, t is the proper time, v is the relative velocity, and c is the speed of light. This equation is derived from Einstein’s postulates that the laws of physics are the same in all inertial frames and that the speed of light is constant, leading to the conclusion that time contracts for objects moving close to the speed of light, resulting in slower experienced time relative to a stationary observer.

If you are on a Ferris wheel rotating at 2 revolutions per minute, your linear tangential speed when clinging midway between the center and the outer rim (halfway) is proportional to the radius. Since speed depends on radius, half the radius means half the tangential speed. The original speed at the outer rim is proportional to the full radius; hence, at half radius, the speed is halved. Therefore, your rotational speed would be half of what it is at the full radius, that is, if the full radius speed is v, at half radius it will be v/2.

On a rotating space habitat, the rotational acceleration at 130 m is g (~9.8 m/s^2). Since acceleration is proportional to the square of the radius (a = v^2/r), if the radius decreases by half to 65 m, the acceleration becomes four times greater, because (r1/r2)^2 = (130/65)^2 = 2^2 = 4. Therefore, the rotational acceleration at 65 m is 4g, or four times Earth's gravity.

If a car traveling at 60 km/h skids 30 meters, then at 180 km/h, the skidding distance can be found using the relationship: skid distance ∝ speed^2. The ratio of the speeds squared is (180/60)^2 = 3^2= 9. So, the new skid distance is 30 m × 9 = 270 m.

The height at which a 1000-kg mass has a potential energy of 1 Joule relative to the ground is h = PE / (m × g) = 1 J / (1000 kg × 9.8 m/s^2) ≈ 0.000102 m, or approximately 0.102 mm.

The average speed of a bicycle traveling 15 km in 30 minutes is calculated by converting time to hours: 30 minutes = 0.5 hours. Speed = distance / time = 15 km / 0.5 hr = 30 km/h.

The average acceleration of a car going from rest to 60 km/h (~16.67 m/s) in 8 seconds is a = Δv / t = 16.67 m/s / 8 s ≈ 2.09 m/s^2.

The initial speed needed to toss a ball so it takes 4 seconds to return to you involves using the symmetry of projectile motion. The initial velocity v = g × t / 2 ≈ 9.8 m/s^2 × 4 s / 2 = 19.6 m/s upward.

For an elastic collision where a 15-kg ball rebounds at 8 m/s, the impulse is Δp = m(v_final - v_initial) = 15 kg × (−8 m/s − 8 m/s) = 15 kg × (−16 m/s) = -240 kg·m/s. The magnitude of impulse is 240 kg·m/s, directed opposite to the initial velocity change.

The distance traveled by an object acted on by a net force can be found using d = (1/2) a t^2, where a = F/m = 1 N / 4 kg = 0.25 m/s^2. Thus, d = (1/2) × 0.25 m/s^2 × (4 s)^2 = 0.125 × 16 = 2 m.

The energy equivalent of 5.0 kg of mass is E= mc^2 = 5.0 kg × (3 × 10^8 m/s)^2 = 5.0 × 9 × 10^16 J = 4.5 × 10^17 J.

If there were no air resistance, the skydiver’s speed after 12 seconds can be calculated using v = g × t = 9.8 m/s^2 × 12 s = 117.6 m/s.

Kerry’s falling speed: a. Speed at impact v = g × t = 9.8 m/s^2 × 1.5 s = 14.7 m/s. b. Height h = (1/2) g t^2 = 0.5 × 9.8 m/s^2 × (1.5 s)^2 = 0.5 × 9.8 × 2.25 ≈ 11.025 m.

Mark’s horizontal distance: using x = v_horizontal × t = 15 m/s × 2 s = 30 m.

When a person stands still with forces balanced, gravity’s force downward and the support force upward are equal in magnitude but act on different objects, so they are not action-reaction pairs. Newton’s third law applies to force pairs acting on different interacting objects, so the forces here are not an action-reaction pair.

Skidding distance at 120 km/h: since skidding distance ∝ velocity^2, (120/60)^2 = 4, so the skidding distance is 20 m × 4 = 80 m.

Leaning to touch toes: stronger legs provide greater muscular control and stability, aiding in maintaining balance and preventing toppling. Longer feet can increase the base of support, making it easier to stay balanced while leaning.

Alice’s crumpled paper falls faster because it encounters less air resistance due to reduced surface area, demonstrating that air resistance impacts falling objects more than gravity’s strength. Alec’s demonstration confirms the effect of shape on air resistance, but not the strength of gravity itself.

The moon orbits Earth at an average radius of about 384,400 km and completes one orbit approximately every 27.3 days. Using v = 2πr / T, the moon’s orbital speed is about 1,022 m/s, which ensures a nearly circular path.

The first postulate of special relativity states that the laws of physics are the same in all inertial frames, meaning no experiment can distinguish a uniform motion from rest. The second postulate asserts that the speed of light in vacuum is constant and the same for all observers, regardless of their relative motion. Together, these postulates challenge classical notions of absolute space and time, leading to the understanding that measurements of these quantities depend on the observer’s frame of reference.

When you toss a ball in a train moving at constant velocity, to an outside observer, the ball’s speed is the sum of your throw speed and the train’s velocity. Because the train moves forward, the external observer sees the ball moving faster than you perceive inside the train, illustrating the relative nature of motion and velocity addition in classical mechanics.

References

• Halliday, D., Resnick, R., & Walker, J. (2014). Fundamentals of Physics (10th ed.). Wiley.
• Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers with Modern Physics (10th ed.). Cengage Learning.
• Tipler,