91影视

A car is parked on a steep hill. Identify the forces on the car.

An elevator suspended by a cable is descending at constant velocity. How many force vectors would be shown on a free-body diagram? Name them

For an object starting from rest and accelerating with constant acceleration, distance traveled is proportional to the square of the time. If an object travels 2.0 furlongs in the first 2.0 s, how far will it travel in the first 4.0 s?

If a force is exerted on an object, is it possible for that object to be moving with constant velocity? Explain.

Is the statement 鈥淎n object always moves in the direction of the net force acting on it鈥� true or false? Explain.

FIGURE shows an acceleration-versus-force graph for a 200 g object. What force values go in the blanks on the horizontal scale?

Figure shows an acceleration-versus-force graph for a 500 g object. What acceleration values go in the blanks on the vertical scale?

Is it possible for the friction force on an object to be in the direction of motion? If so, give an example. If not, why not?

Figure shows the acceleration of objects of different mass that experience the same force. What is the magnitude of the force?

Suppose you press your physics book against a wall hard enough to keep it from moving. Does the friction force on the book point

(a) into the wall,

(b) out of the wall,

(c) up,

(d) down, or

(e) is there no friction force? Explain.