Exam 5: Further Applications of Newtons Laws

A box rests on the (horizontal) back of a truck. The coefficient of static friction between the box and the surface on which it rests is 0.24. What maximum distance can the truck travel (starting from rest and moving horizontally with constant acceleration) in 3.0 s without having the box slide?

A sample of blood is placed into a centrifuge of radius 15.0 cm. The mass of a red corpuscle is 3.0 *10-16 kg, and the centripetal force required to make it settle out of the plasma is 4.0 * 10-11 N. At how many revolutions per second should the centrifuge be operated?

A 1.8-kg block is released from rest at the top of a rough 30 $\degree$ inclined plane. As the block slides down the incline, its acceleration is 3.0 m/s2 down the incline. Determine the magnitude of the force of friction acting on the block.

A race car travelling at 100 m/s during a race at Bathurst enters an unbanked turn of 400 m radius. The coefficient of (static) friction between the tyres and the track is 1.1. The track has both an inner and an outer wall. Which statement is correct?

What is the net force on a 10-kg solid steel sphere falling in air at terminal speed?

The coefficient of static friction for the tyres of a race car is 0.950 and the coefficient of kinetic friction is 0.800. The car is on a level circular track of 50.0 m radius on a planet where $g=2.45 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}$ compared to Earth's $g=9.80 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}$ . If the car is to be able to travel at the same speed on the planet as on Earth, the radius of the track on the planet must be ____ times as large as the radius of the track on Earth.

The coefficient of static friction for the tyres of a race car is 0.950 and the coefficient of kinetic friction is 0.800. The car is on a level circular track of 50.0 m radius on a planet where $g=2.45 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}$ compared to Earth's $g=9.80 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}$ . The maximum safe speed on the track on the planet is ____ times as large as the maximum safe speed on Earth.