A child throws a ball, which hits a vertical wall at a height of 1.3m above the ball’s release point. The speed of the ball at impact is 10.2m/s. What was the initial speed of the ball?  How much work was done raising the ball up those 1.2m? Was any work done in the horizontal direction? Please explain your answer. [

A 4.5-kg block slides down a frictionless incline making an angle of 55.0° with the horizontal. (a) What is the total work done on the block when the block slides 1.4 m (measured along the incline)? (b) What is the speed of the block after it has slid 1.2 m if it starts from rest? m/s (c) What is its speed after 1.2 m if it starts with an initial speed of 1.6 m/s? m/s You can use the definition of work as the scalar product of a constant force and displacement to find the work done by each force acting on the block. Then use the work- kinetic energy theorem the find the speed of the block at any given location and for any initial kinetic energy it may have.

A 0.32-kg particle has a speed of 5.0 m/s at point A and kinetic energy of 8.1 J at point B. (a) What is its kinetic energy at A? (b) What is its speed at point B? m/s (c) What is the total work done on the particle as it moves from A to B?

A block of mass m=1.5kg is released from rest at an unknown height h. The coefficient of friction between the block and the incline oriented at an angle of 0=56° is Hk=0.21. If the speed of the block v=4.1m/s when it leaves the inclined plane, determine the work done by the force of gravity. Take g =9.81m/s? and express your final result using one decimal place. m m

A cheerleader lifts his 68 kg partner straight up off the ground a distance of 0.72 m before releasing her. Assume the partner’s velocity is zero at the beginning and the end of the lift. The acceleration of gravity is 9.8 m/s2 . If he does this 22 times, how much work has he done? Answer in units of J.

The force acting on a particle varies as in the figure below. (The x axis is marked in increments of 0.250 m.) Find the work done by the force as the particle moves across the following distances. (a) from x = 0 m tox = 2.00 m(b) from x = 2.00 m to x = 3.00 m(c) from x = 0 m to x = 3.00 m

A different robot begins pushing a 10kg box that was already moving at 0.5m/s [Right] along a surface with a coefficient of kinetic friction of 0.15. The robot pushes with only 3N [Right] of force. What is the acceleration of the box?  Using the Work-Energy theorem, calculate how much work the robot does on the box accelerating it from 0.5m/s [Right] to 2m/s [Right]. What distance did the robot push the box? Use kinematics to check your work.

Starting from rest, a 5.40-kg block slides 3.40 m down a rough 30.0° incline. The coefficient of kinetic friction between the block and the incline is µ, = 0.436. (a) Determine the work done by the force of gravity. (b) Determine the work done by the friction force between block and incline. (c) Determine the work done by the normal force. (d) Qualitatively, how would the answers change if a shorter ramp at a steeper angle were used to span the same vertical height?

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A tennis ball of mass m = 0.091kg is thrown straight up with an initial speed v_{0} = 14m / s Let the gravitational potential energy be zero the initial height of the tennis ball a.what is the maximum height , h in meters the ball reaches B. What is the work done by gravity W_{g} Joules, during the ball's flight to its maximum height?