When you weigh yourself on good old terra firma (solid ground), your weight is $142 \mathrm{lb}$. In an elevator your apparent weight is $121 \mathrm{lb}$. What are the direction and magnitude of the elevator's acceleration?

A hockey puck is acted on by one or more forces, as shown in the given figure. Rank the four cases, A, B, C, and D, in order of the magnitude of the puck's acceleration, starting with the smallest. Indicate ties where appropriate.

Suppose a rocket launches with an acceleration of $30.5 \mathrm{~m} / \mathrm{s}^2$. What is the apparent weight of an $92-\mathrm{kg}$ astronaut aboard this rocket?

Assume the elevator is at rest. rank the magnitude of the forces.

A skateboarder on a ramp is accelerated by a nonzero net force. For each of the following statements, state whether it is always true, never true, or sometimes true. The acceleration of the skateboarder is at right angles to the net force.

A skateboarder on a ramp is accelerated by a nonzero net force. For each of the following statements, state whether it is always true, never true, or sometimes true.The skateboarder is moving in the direction of the net force.

You pull upward on a stuffed suitcase with a force of $105 \mathrm{~N}$, and it accelerates upward at $0.725 \mathrm{~m} / \mathrm{s}^2$. What is the mass of the suitcase?

A skateboarder on a ramp is accelerated by a nonzero net force. For each of the following statements, state whether it is always true, never true, or sometimes true. The skateboarder is instantaneously at rest.

You pull upward on a stuffed suitcase with a force of $105 \mathrm{~N}$, and it accelerates upward at $0.705 \mathrm{~m} / \mathrm{s}^2$. What are the weight of the suitcase?

A farm tractor tows a 3700-kg trailer up an $18^{\circ}$ incline with a steady speed of $3.2 \mathrm{~m} / \mathrm{s}$. What force does the tractor exert on the trailer? (Ignore friction.)

To give a 19-kg child a ride, two teenagers pull on a 3.7-kg sled with ropes. Both teenagers pull with a force of 55 N at an angle of $35^{\circ}$ relative to the forward direction, which is the direction of motion. In addition, the snow exerts a retarding force on the sled that points opposite to the direction of motion and has a magnitude of 57 N. Find the acceleration of the sled and child.

A skateboarder on a ramp is accelerated by a nonzero net force. For each of the following statements, state whether it is always true, never true, or sometimes true. The acceleration of the skateboarder is in the same direction as the net force.

An object acted on by three forces moves with constant velocity. One force acting on the object is in the positive $x$ direction and has a magnitude of $6.5 \mathrm{~N}$; a second force has a magnitude of $4.4 \mathrm{~N}$ and points in the negative $y$ direction. Find the direction and magnitude of the third force acting on the object.

A 65-kg skier speeds down a trail, as shown in Figure . The surface is smooth and inclined at an angle of $22^{\circ}$ with the horizontal. Determine the normal force acting on the skier.