2) A constant net force of 75 N acts on an object initially at rest through a pa

Question

2) A constant net force of 75 N acts on an object initially at rest through a paralle distanc oht is ts final (a) What is the final kinetic energy of the object? (b) If the object has a mass speed? ANS: (a) 45 J; (b) 21.2 m/s I distance of 0.6 m. of 0.2 kg, what is its final 3) A 40 N crate starting at rest slides down a frictionless 6 meter high (not long) ramp inclined at the horizontal. What is the speed of the crate at the bottom of the incline? ANS: 10.8 m/s n athlete jumping vertically on a trampoline leaves the surface with a velocity of 8.5 m/s upward What maximum height does she reach? ANS: 3.7 m Find the height from which you would have to drop a ball so that it would have a speed of 9 m/s just before it reaches the ground? 5) ANS: 4.1 m A 50 kg pole vaulter running at 10 m/s vaults over the bar. Her speed when she is above the bar is 1 m/s. Neglecting air resistance and any energy absorbed by the pole, determine her altitude as she crosses the bar. ANS: 5 m 6) 7) A child and a sled with a combined mass of 50 kg slide down a frictionless slope. If the sled starts from rest and has a speed of 13 m/s at the bottom, what is the height of the hill? ANS: 8.6 m 8) A bead of mass m 5 kg is released from point A and slides on the frictionless track shown below. Determine (a) the bead's speed at point B and (b) the bead's speed at point C ANS: (a) 5.9 m/s; (b) 7.7 m/s 20 200

Explanation / Answer

Q1. A constant net force...
Soln.
(a)
W = Fd = KEf – KEi
W = 75 * 0.60 = KEf
KEf = 45 joules
(b)
KE = ½ mv^2 = 45 joules
v = sqrt(2 * 45 / 0.20) = 21.2 m/s

Q2.
1/2 mv^2 = mgh
1/2*(40/9.8)v^2 = 40* 6
=> v = 10.8 m/s

Pls post other ques separately

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