A 1.2ft diameter ball is thrown onto a rough surface, such that it has a velocity of 6ft/s and a backspin angular velocity of w. If it is to stop backspinning at the same instant as the velocity is 0, the backspin w in rad/s is what? HINT: The answer is independent of the mass and coefficient of friction.
a. 17.8
b. 22.0
c. 25.0
d. 28.1

*Please see attachment for diagram and figures; please show your work.

Let us assume the friction force will be f, acting backward, therefore, the force f will help to reduce the back spinning wo to 0, and and also reduce the forward linear speed ...

The hoop (thin ring) has a mass of 5 kg and is released down the inclined plane such that it has a backspin angular speed = 8 rad/s and its center has a velocity = 3 m/s as shown. If the coefficient of kinetic friction between the hoop and the plane is 0.6, determine the hoop's angular velocity in 1 s.
(See attached file for

A tennis player hitting from the baseline develops a forward velocity of 70 ft/s and a backspin of 5000 rpm. The ball weights 0.125 lb and has a diameter of 2.56 in. Assume standard pressure and 70 Fahrenheit and neglect the drag force. Including the lift provided by the backspin, how much will the tennis ball have dropped by th

By striking a pool ball below its mid-line, you can cause it to translate to the right while rotating counterclockwise (slipping). Assume a coefficient of friction equal ot 0.65, a diameter of 7 cm, a mass of 0.11 kg, a velocity of 5 m/sec and a spinn of 30 rad/sec. How far will the ball travel before it translations to pure rol

See attached file for full problem description
Escape velocity. We suppose that r = -gR^2/r^2. Suppose that a rocket is fired straight up, from the surface of the Earth with a velocity that is exactly half of the escape velocity. How high will the rocket go?

A hill has a height h. A child on a sled (total mass m) slides down starting from rest at the top.
Does the velocity at the bottom depend on the angle of the hill if:
a) It is icy and there is no friction?
b) There is friction (deep snow)?

A dynamics student is called on to investigate a two car collision. It is known that car A sruck car B (see attahment). mA = 2000 kg and mB = 1200 kg. Both cars A and B then skidded 8.0 m. It apears from the damage that car A struck car B at a relative speed of 12 m/s.
Find the speed of car A just before collision. Assume a

If an object slides directly down an inclined place, at a constant velocity of 6 m/s, how large is the coefficient of kinetic friction if the plane make an angle of 25 degrees with the horizontal?

Using the log law, determine the velocity distribution for Couette flow between parallel plates a distance h apart, with U = the velocity of the top plate.
Prove that the centerline velocity is:
(Re/(4*f))^.5=(1/kappa)*ln((.5)*(Re*f)^.5)+B
Re=Uh/nu
f=Tau_wall*h/(mu*U)

Dynamics 12.8
A car has been traveling up along a 2 percent grade at a constant speed of 55 miles/hr. If the driver does not change the setting of the throttle or shift gears as the car reaches the top of the hill, what will be the acceleration of the car as it starts moving down the 3 percent grade?
Dynamics 13.7
A 24-