A stone with a mass of 120 g is fired from a catapult into the air at an angle of 45° to the horizontal and a speed of 25 m/s.Air resistance should be ignored. What is the kinetic energy of the stone (in m/s) as it hits the ground and as it leaves the sling? answer : 38J

Your task is to defend the Disney Castle from attackers. You have a catapult with which you can lob a rock with a launch speed of 14.2 m/s. from the courtyard over the walls onto the attackers at an elevation of 7.20 m. below that of the courtyard. What is the speed with which the rock will hit the ground at the attacker’s camp? Note: Use the Law of Conservation of Mechanical Energy.

A 1000-kg car accelerates from 0 to 15 m/s in 5.0 s with negligible friction and air resistance. What is the average power delivered by the engine? 7500 W O 45000 W O 1500 W O 22500 W O 112500 W

A student, starting from rest, slides down a water slide. On the way down, a kinetic frictional force (a nonconservative force) acts on her. The student has a mass of 81 kg, and the height of the water slide is 11.8 m. If the kinetic frictional force does -5.1 × 103 J of work, how fast is the student going at the bottom of the slide?

You are out on a nice bike ride in the mountains. You and the bicycle together have a mass of 83 kg. Up ahead, there is a huge hill to climb. You stop and drink some water and start to climb. The climb is very hard work. You entertain yourself with your nifty bike computer, which is reporting a power output of 400.0 W! At the end, you've climbed 128 m vertically in 4 minutes and 32 seconds! a) Assuming your power output was constant, how much work did you do during your climb? b) What is the energy transfer equation during this climb? c) Assuming your power output was constant, and no energy was lost, what was your final kinetic energy (remember you started off at rest?

A block of mass ?=0.350kg is released from rest, from a curved ramp of height h= 42.0 cm (point A in the figure). The block slides down frictionless to the bottom of the ramp to point B. a) What is work done by gravity when the block moves from A to B? b) What is the speed of the block at the bottom of the ramps (point B in the figure)? c) The box continuesto slide frictionless and compress a spring a distance Δ?=8.20cm until it stops at point C. What is the spring constant k of the spring? d)What is the elastic potential energy stored in the spring when the block is at point C?

You push a file cabinet up a frictionless ramp tilted at 10°with horizontal. The file cabinet has a mass of 100 kg and you are pushing with a 700 N force in the direction up along the ramp. The file cabinet has initial speed of 2.0 m/s. It’s moved 8.0 m up along the ramp. Match the answers with questions. the initial kinetic energy of the cabinet (Ki)                                                                                                                    the final kinetic energy of the cabinet (Kf)                                                                                                                    the change in kinetic energy of the cabinet (ΔK) A. -200 J B. -4208 J C. -4408 J D. 0 J E. 4008 J F. 4208 J G. -4008 J H. 4408 J I. 200 J

A bicyclist starting from rest applies a force of F = 239 N to ride his bicycle across flat ground for a distance of d = 210 m before encountering a hill making an angle of θ = 17 degrees with respect to the horizontal. The bicycle and rider have a mass of m = 120 kg combined. In this problem, you can ignore air resistance and other losses due to friction.How much work, W in joules, did the rider do before reaching the hill? What is the bicycle's speed, v in m/s, just before the hill? If the cyclist starts coasting at the bottom of the hill, what distance, di in meters, does the bike travel up the incline?

A 1200-kg sports car is advertised to accelerate from 0-100 km/h (27.78 m/s) in 3.00 s. What is the power output of the car in hp? 1 hp = 746 W 01 207 hp 325 hp 200 hp 175 hp

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.