38. In an emergency stop to avoid an accident, a shoulder-strap seat belt holds a 60-kg passenger firmly in place. If the car were initially traveling at 90 km/h and came to a stop in 5.5 s along a straight, level road, what was the average force applied to the passenger by the seatbelt?

66. A person standing on a bridge at a height of 115 m above a river drops a 0.250-kg rock. (a) What is the rock's mechanical energy at the time of release relative to the surface of the river? (b) What are the rock's kinetic, potential, and mechanical energies after it has fallen 75.0 m? (c) Just before the rock hits the water, what are its speed and total mechanical energy? (d) Answer parts (a)-(c) for a reference point (y = 0) at the elevation where the rock is released. (Neglect air resistance.)

52. Imagine that you swing about your head a ball attached to the end of a string. The ball moves at a constant speed in a horizontal circle. (a) Can the string be exactly horizontal? Why? (b) If the mass of the ball is 0.250 kg, the radius of the circle is 1.50 m, and it takes 1.20 s for the ball to make one revolution, what is the ball's tangential speed? (c) What centripetal force are you imparting to the ball via the string?

56. A clock uses a pendulum that is 75 cm long. The clock is accidentally broken, and when it is repaired, the length of the pendulum is shortened by 2.0 mm. Consider the pendulum to be a simple pendulum. (a) Will the repaired clock gain or lose time? (b) By how much will the time indicated by the repaired clock differ from the correct time (taken to be the time determined by the original pendulum in 24 h)? (c) If the pendulum string were metal, would the surrounding temperature make a difference in the timekeeping of the clock? Explain.

A 4.0 kg toy race car can move along an x axis. The figure below gives Fx of the force acting on the car, which begins at rest at time t = 0. (The vertical axis is marked in increments of 2 N.)
See the attached document for the necessary graph.
(a) What is the momentum of the car at t = 6.0 s
(b) What is the moment

A major-league pitcher can throw a baseball in excess of 41.0 m/s. Assume the pitcher throws the ball horizontally to a catcher who is 17.0 m away.
a) Sketch a y vs. x graph.
b) How long does it take for the ball to reach the catcher?
c) How far does the ball drop by the time it reaches the catcher?

A particle with mass m and electric charge q is bound by the Coulomb interaction to an infinitely massive particle with electric charge -q. At t=0 its orbit is (approximately) a circle of radius R. At what time will it have spiralled into R/2? (Assume that R is large enough so that you can use the classical radiation theory than

A 4.0 kg toboggan rests on a frictionless icy surface, and a 2.0 kg block rests
on top of the toboggan. The coefficient of static friction µs between the block
and the surface of the toboggan is 0.58, whereas the kinetic friction
16.T op
coefficient is 0.48. The block is pulled by a horizontal force of 30 N as shown.
a. Ca

Rutheford successfully used classicalmechanics to account for the scattering pattern of alpha particles by heavy nuclei: he treated the alpha particle as a point mass that follows a hyperbolic trajectory under the repulsion of a ﬁxed point nucleus. But the de Broglie view of the wave nature of particles raises some awkward qu

An astronaut is being tested in a centrifuge. The centrifuge has a radius of 10 m and, in starting, rotates according to theta = (0.30 rad/s?t? where t is in seconds and theta is in radians. When t = 5.0 s, what are the magnitudes of the astronaut's
(a) rotational velocity,
(b) translational velocity,
(c) tangential accele

A man with a mass of 65 kg skis down a friction-less hill that is 4.4m high. At the bottom of the hill the terrain levels out. As the man reaches the horizontal section, he grabs a 19-kgbackpack and skis off a 1.0 m-high ledge. At what horizontal distance from the edge of the ledge does the man land?

1. State the conservation of momentum and kinetic energy in collisions in classicalmechanics and relativistic mechanics
2. derive the relativistic kinetic energy.
3. Derive the total relativistic force as a function of momentum.
please show the solutions in detail, stepwise.

1. You are loading a spring loaded dart gun and do an amount of work W such that the spring is only 1/3 compressed. How much additional work must you do to fully compress it from 1/3 to fully compressed? Answer in terms of W.
2. A large man tosses a small child onto a large pile of leaves. During the toss, the man exerts ___

A 1.2 kg grindstone in the shape of a uniform cylinder of radius 0.25 m acquires a rotational rate of 1800 rev/s from rest over a 6.0 s interval at constant angular acceleration. Calculate the torque delivered by the motor.