A Rope Pulls A Mass Up An Incline From A Height Of 0 M ✓ Solved

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A rope pulls a mass M up an incline from a height of 0 m to

1. The work done by the tension WT = a) MgH b) -MgH sin θ c) -MgH d) 0

2. The NET work on M being up an incline from a height of 0 m to a height H at a constant speed is = a) MgH b) -MgH sin θ c) -MgH d) 0

3. A block with mass m travels with velocity v toward a spring with spring constant k on a frictionless surface. The spring is compressed distance xm = from equilibrium x = 0. a) √(m/k) v b) √(k/m) v c) kv/m d) Not enough information.

4. A skater of mass m travels to a wall in the negative x direction with velocity v, bounces off of the wall, then travels in the positive x direction with the same velocity v. The magnitude of the change in momentum is a) 0 b) 2mv c) mv d) mv

5. The force F as a function of position x is shown. The work W done between x1=4.0 m and x2=6.0 m a) 20 J b) 40 J c) 80 J d) 10 J

Question 1: Initially mass m1=1.0 kg moves with velocity v1i=4.0 m/s in the positive x-direction toward mass m2=5.0 kg that is also moving at v2i=1.0 m/s positive x-direction. After the masses collide m2 continues moving to the right at v2f =2.0 m/s. A. Calculate the final velocity of m1, vf1. Indicate the direction. B. Determine if the collision is elastic or inelastic. Show quantitatively.

Question 2: Suppose F = t² – t⁵ represents a force that acts on the interval ti=0 s and tf =1 s. A. Calculate the impulse associated with this force on that interval. B. Calculate the average force Fave on that interval.

Question 3: An asteroid of mass m=8.7×10¹⁶ kg falls to Earth (ME=5.98×10²⁴ kg, RE=6.4×10⁶ m) from a height h=7RE. A. Calculate the force of gravity FG between the Earth and the asteroid at height h. B. If the initial velocity of the asteroid is approximately zero vi=0, calculate final velocity vf when it lands on the surface of Earth.

Question 4: A force F=6x⁵ acts between x0=0 and x=2. Calculate the work W done on this interval. B. A constant force F=3i + 1j acts between r0=0 and r=1i + 3j. What is the work W done on this interval? C. A potential energy is described as U=-xy². Find the x- and y-components of the force, Fx and Fy respectively.

Question 4: A soccer ball of mass msb=0.43 kg kicked due west at velocity vsb,i=27.0 m/s during a practice collides with a rock mr=0.3 kg that is initially at rest. A. Draw a picture of the system. B. Use conservation of momentum to calculate the y-component of the momentum of the rock py,r,f after the collision. C. Use conservation of momentum to calculate the x-component of the momentum of the rock px,r,f after the collision. D. Calculate the magnitude pr,f and direction θr,f of the rock after the collision.

EXTRA CREDIT: Is the collision elastic or inelastic?

Question 5: A block of mass m=5.0 kg and velocity v0 travels toward an incline at angle θ=20.0° as shown. Just before the mass encounters the incline, it experiences a d=1.00 m patch of ground with friction (μk=0.1). Just at the end of this patch, the velocity of the mass is v=25.0 m/s. A. Calculate the work done by friction Wfriction. B. Calculate the velocity v0 before the mass experienced friction. C. Calculate the maximum height Hmax the mass reaches on the incline. EXTRA CREDIT: If the incline had the same coefficient of friction as the patch (μk=0.1), calculate the new maximum height H'max the mass reaches on the incline.

Paper For Above Instructions

The physics questions outlined in the provided exam cover various concepts including forces, momentum, work, and energy. The key principles needed to solve these problems involve the application of Newton’s laws, conservation of momentum, and the work-energy theorem.

To tackle the first question regarding the work done by the tension when pulling a mass M up an incline, we can start by discussing the forces involved. When the mass is raised to a height H, the work done by the tension is indeed equal to the gravitational potential energy change, thus: Wₜ = MgH. This holds true as long as the mass is moving at a constant speed, meaning the net work done is zero (the tension balances the gravitational force).

For the net work done when drawing the mass up the incline, since the speed remains constant, the net work should also be zero. To justify this, we apply the work-energy theorem which states that the net work done on the mass is equal to its change in kinetic energy, and since there's no change in speed, the net work is consequently zero.

Moving on to the spring question, it addresses the compression of a spring by a mass moving at velocity v. The relationship between kinetic energy and spring potential energy leads to the conclusion that the compression distance will affect the energy storage in the spring, determined by the equation for spring force: F = kx. Using energy conservation, we find if the spring is compressed to a certain distance, the mass must possess enough kinetic energy to account for that – as described by: KE_initial = KE_final + PE_spring.

As we dissect the scenario with the skater colliding with a wall and then bouncing off, we define momentum as p = mv. The change in momentum here is indeed significant; before the collision, the momentum is negative and after, it becomes positive. Therefore, the change is Δp = mv_final - (-mv_initial) = 2mv.

Concerning the Force against position question, evaluating the integral of the force function over the defined range [x₁, x₂] gives us the work done. Thus, we can compute this using the provided function of force over the interval between positions.

In questions involving collisions, momentum conservation laws are pivotal. For example, when two masses collide, one must apply the principle of conservation of momentum: m₁v₁i + m₂v₂i = m₁v₁f + m₂v₂f. By substituting known values into this equation, one can solve for the unknown velocities post-collision.

As for the asteroid falling towards Earth, calculating gravitational force involves leveraging Newton’s law of gravitation: F_G = G(m1*m2)/(r^2). The final velocity right before impact can be derived from energy conservation as well, converting potential energy into kinetic energy.

Lastly, regarding the soccer ball and block momentum problems while taking into account the effects of friction on motion, we would assess directional momentum components post-collision and leverage trigonometric principles for resolving momentum vectors in 2D.

In all these physics problems, careful illustration and labeling of figures as well as a thorough follow-through with dimensional analysis are critical in substantiating the methods and solutions presented.

References

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