Exam 6: Applications of Newtons Laws

A roller coaster car is on a track that forms a circular loop in the vertical plane. If the car is to just maintain contact with track at the top of the loop, what is the minimum value for its centripetal acceleration at this point?

A 50.0-kg box is being pushed along a horizontal surface. The coefficient of kinetic friction between the box and the ground is 0.350. What horizontal force must be exerted on the box for it to accelerate at 1.20 m/s²?

A 3.00-kg mass rests on the ground. It is attached to a string which goes vertically to and over an ideal pulley. A second mass is attached to the other end of the string and released. The 3.00-kg mass rises 50.0 cm in 1.00 s. How large was the other mass?

You are driving your car and set your sunglasses on the dashboard. When you make a left turn, the sunglasses go sliding off to the right. Explain.

FIGURE 6-2 -In Figure 6-2 the scale at left is attached to the ceiling and a mass of 1.00 kg hangs from it. It reads 9.81 N. The identical scale at the right is connected by perfect strings passing over perfect pulleys to two 1.00 kg masses hanging vertically at the end of the strings. The scale at right reads

FIGURE 6-12 -Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.0 kg and can slide along a smooth plane inclined 30° to the horizontal. What is the mass of block B if the system is in equilibrium?

When an object is in translational equilibrium, the net force acting on the object is non-zero.

When an object experiences uniform circular motion, the direction of the net force is

The stretch of a spring and the force it exerts are inversely proportional.

The banking angle for a properly banked curve does not depend on the mass of the car going over it.

FIGURE 6-10 -A 10-kg sign is held by two ropes as shown in Figure 6-10. What is the tension on rope B?

FIGURE 6-12 -Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.00 kg and can slide along a smooth plane inclined 30.0° to the horizontal. Block B has a mass of 2.00 kg. What is the acceleration of mass B?

The force fo static friction between two surfaces is parallel to the surface of contact, and in in the direction that opposes relative motion.

A 2-kg ball is moving with a constant speed of 5 m/s in a horizontal circle whose radius is 50 cm. What is the acceleration of the ball?

When a curve is properly banked a passenger in a car traveling on it at the designed speed does not feel a lateral force.

FIGURE 6-15 -A 20.0-gram mass is attached to a 120 cm-long string as shown in Figure 6-15. The angle α is measured to be 18.0°. What is the speed of the mass?

FIGURE 6-11 -Refer to Figure 6-11. Block A has a mass of 3.00 kg and rests on a smooth table and is connected to block B, which has a mass of 2.00 kg, after passing over an ideal pulley, as shown. Block B is released from rest. What is the acceleration of the masses?

A flatbed truck is carrying a 20.0-kg crate up a sloping road. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum angle of slope that the truck can climb at constant speed if the crate is to stay in place?

FIGURE 6-13 -Refer to Figure 6-13. Block A has a mass of 5.00 kg, block B has a mass of 3.00 kg and block C has a mass of 2.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the tension in the string connecting blocks A and B?

For uniform circular motion, the velocity and acceleration vectors are perpendicular to each other at every point in the path.