Physics Answers

A particle of mass m has speed v = c/x, where c is a constant and x is the displacement. At t=0, x=

x Find the force

a) F(x)

b) F(t)

What is the angular velocity of a car whose tire radius is 0.300 meter when the car travels at a linear speed of 15 m/s?

A 50-N force is applied at the end of the wrench handle that is 24-cm long. The force is applied in a direction perpendicular to the handle as shown.

A. What is the torque applied to the nut by the wrench?

B. What would the torque be if the force were applied half-way up the handle instead of at the end?

A uniform rod of mass 2 kg and length of 2.0 m is pivoted about an axis perpendicular to the rod and 50 cm from its left end. Find the rotational inertia about this axis.

A ball is released from a height of 20N. Calculate

a. The time it takes to fall

b. The velocity to which it hits the ground

A plane flying at 80 m/s is uniformly accelerated at the rate of 2.0 m/s2. What is

the distance it will travel during a 10 s interval after acceleration begins?

What will happen if an ice skater spinning on one of her toes extends her arms? 

a. Her moment of inertia will increase but her angular velocity will decrease.

b. Her moment of inertia and angular velocity will increase.

c. Her moment of inertia and angular velocity will decrease.

d. Her moment of inertia will decrease but her angular velocity will increase.

For a rigid body to be in equilibrium, _________ 

a. the net torque on it must be zero

b. the net force acting on it must be zero

c. the net force and the net torque acting on it must be zero

d. it must be stable

In considering the moment of inertia of a body, it is convenient to assume as if all its mass were concentrated at a single point from the center of rotation. This distance is called ___________ 

radius of gyration

center of gravity

center of mass

lever arm

Which has a greater moment of inertia? 

short, thin leg

long, thin leg

short, fat leg

long, fat leg