A camera weighing 15 N falls from a small drone hovering 35 m overhead and enters free fall. What is the gravitational potential energy change of the camera from the drone to the ground if you take a reference point of a. the ground being zero gravitational potential energy? APE b. The drone being zero gravitational potential energy? APE= What is the gravitational potential energy of the camera (with the reference point of zero gravitational potential energy taken to be a second person looking out of a building 30 m from the ground) c. before it falls from the drone? PE= d. after the camera lands on the ground? PE Submit Question

Integrated Concepts (a) What force must be supplied by an elevator cable to produce an acceleration of 0.800 m/s2 against a 200-N frictional force, if the mass of the loaded elevator is 1500 kg? (b) How much work is done by the cable in lifting the elevator 20.0 m? (c) What is the final speed of the elevator if it starts from rest? (d) How much work went into thermal energy?

A camera weighing 10 N falls from a small drone hovering 20 m overhead and enters free fall. What is the gravitational potential energy change of the camera from the drone to the ground if you take a reference point of (a) the ground being zero gravitational potential energy? (b) The drone being zero gravitational potential energy? What is the gravitational potential energy of the camera (c) before it falls from the drone and (d) after the camera lands on the ground if the reference point of zero gravitational potential energy is taken to be a second person looking out of a building 30 m from the ground?

One person drops a ball from the top of a building while another person at the bottom observes its motion. Will these two people agree (a) on the value of the gravitational potential energy of the ballEarth system? (b) On the change in potential energy? (c) On the kinetic energy of the ball at some point in its motion?

A ball is connected to a light spring suspended vertically as shown in Figure 6.17. When pulled downward from its equilibrium position and released, the ball oscillates up and down. (i) In the system of the ball, the spring, and the Earth, what forms of energy are there during the motion? (a) kinetic and elastic potential (b) kinetic and gravitational potential (c) kinetic, elastic potential, and gravitational potential (d) elastic potential and gravitational potential (ii) In the system of the ball and the spring, what forms of energy are there during the motion? Choose from the same possibilities (a) through (d).

. The fastest that a human has run is about 12 m/s. (a) If a pole vaulter could run this fast and convert all of her kinetic energy into gravitational potential energy, how high would she go? (b) Compare this height with the world record in the pole vault.

Space debris left from old satellites and their launchers is becoming a hazard to other satellites. (a) Calculate the speed of a satellite in an orbit 900 km above Earth’s surface. (b) Suppose a loose rivet is in an orbit of the same radius that intersects the satellite’s orbit at an angle of 90 . What is the velocity of the rivet relative to the satellite just before striking it? (c) If its mass is 0.500 g, and it comes to rest inside the satellite, how much energy in joules is generated by the collision? (Assume the satellite’s velocity does not change appreciably, because it mass is much greater than the rivets’s.)

A small block of mass m = 200 g is released from rest at point along the horizontal diameter on the inside of a frictionless, hemispherical bowl of radius R = 30.0 cm (Fig. P8.43). Calculate (a) the gravitational potential energy of the block-Earth system when the block is at point relative to point . (b) the kinetic energy of the block at point . (c) its speed at point B, and (d) its kinetic energy and the potential energy when the block is at point . Figure P8.43 Problems 43 and 44.

A cat’s crinkle ball toy of mass 15 g is thrown straight up with an initial speed of 3 m/s. Assume in this problem that air drag is negligible. (a) What is the kinetic energy of the ball as it leaves the hand? (b) How much work is done by the gravitational force during the ball’s rise to its peak? (c) What is the change in the gravitational potential energy of the ball during the rise to its peak? (d) If the gravitational potential energy is taken to be zero at the point where it leaves your hand, what is the gravitational potential energy when it reaches the maximum height? (e) What if the gravitational potential energy is taken to be zero at the maximum height the ball reaches, what would the gravitational potential energy be when it leaves the hand? (f) What is the maximum height the ball reaches?

A particle of m has a velocity of . Is its kinetic energy given by ? If not, what is the correct expression?