Exam 6: Force and Motion II

A giant wheel, having a diameter of 40 m, is fitted with a cage and platform on which a man of mass m stands. The wheel is rotated in a vertical plane at such a speed that the force exerted by the man on the platform is equal to his weight when the cage is at X, as shown. The net force on the man at point X is:

An object moves in a circle. If the mass is tripled, the speed halved and the radius unchanged then the magnitude of the centripetal force must be multiplied by a factor of:

Which of the following five graphs is correct for a particle moving in a circle of radius r at a constant speed of 10 m/s?

A 24-N horizontal force is applied to a 40-N block initially at rest on a rough horizontal surface. Ifthe coefficients of friction are $\mu$ _s = 0.5 and $\mu$ _k = 0.4, the magnitude of the frictional force on the block is:

A 0.2-kg stone is attached to a string and swung in a circle of radius 0.6 m on a horizontal and frictionless surface. If the stone makes 150 revolutions per minute, the tension force of the string on the stone is:

Block A, with a mass of 10 kg, rests on a 30 $\degree$ incline. The coefficient of kinetic friction is 0.20. The attached string is parallel to the incline and passes over a massless, frictionless pulley at the top. Block B, with a mass of 3.0 kg, is attached to the dangling end of the string. The acceleration of B is:

The coefficient of kinetic friction:

Circular freeway entrance and exit ramps are commonly banked to handle a car moving at 13 m/s. To design a similar ramp for 26 m/s one should:

A 400-N block is dragged along a horizonatl surface by an applied force as shown. The coefficient of kinetic friction is u_k = 0.4 and the block moves at constant velocity. The magnitude of is:

A block is first placed on its long side and then on its short side on the same inclined plane. The block slides down the plane on its short side but remains at rest on its long side. A possible explanation is:

A crate is sliding down an incline that is 35 $\degree$ above the horizontal. If the coefficient of kinetic friction is 0.40, the acceleration of the crate is: