Exam 6: Applications of Newtons Laws

FIGURE 6-7 -A workman lowers a 30.0-kg load using the ideal pulley arrangement shown in Figure 6-7. He allows the rope to slide in his hands, thus exerting a downward force of 100 N on the rope. What is the acceleration of the load?

FIGURE 6-1 -In Figure 6-1, the block of mass m is at rest on an inclined plane that makes an angle θ with the horizontal. The normal force F acting on the block must be such that

An airplane is flying with constant speed along a horizontal circle. Is the direction of its acceleration constant?

FIGURE 6-7 -A 30.0-kg load is being raised by a force of 180 N using the ideal pulley arrangement shown in Figure 6-7. What is the acceleration of the load?

A 50.0-kg box is being pushed along a horizontal surface by a force of 250 N directed 28.0° below the horizontal. The coefficient of kinetic friction between the box and the surface is 0.300. What is the acceleration of the box?

Is it possible for an object moving with a constant speed to accelerate? Explain.

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. How long does it take block B to travel 80.0 cm?

FIGURE 6-1 -In Figure 6-1, the block of mass m is at rest on an inclined plane that makes an angle θ with the horizontal. The force of static friction f must be such that

A car moving at 10.0 m/s encounters a bump that has a circular cross-section with a radius of 30.0 m. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the top of the bump?

A 50.0-kg box is being pulled along a horizontal surface by means of a rope that exerts a force of 250 N at an angle of 32.0° above the horizontal. The coefficient of kinetic friction between the box and the surface is 0.350. What is the acceleration of the box?

The banking angle in a turn on the Olympic bobsled track is not constant, but increases upward from the horizontal. Coming around a turn, the bobsled team will intentionally "climb the wall," then go lower coming out of the turn. Why do they do this?

You are driving in your car with a sack of groceries in the seat next to you. You see a light change and you slow down and the sack remains on the seat. Suddenly the car in front of you slams on the brakes, and you are forced to brake harder. The groceries slide off the seat. Explain what happened.

When a car goes around a curve, it has a tendency to skid outwards. Is the frictional force between the tires and the ground that keeps the car from skidding kinetic or static?

A roller coaster car (mass = M) is on a track that forms a circular loop (radius = r) in the vertical plane. If the car is to just maintain contact with the track at the top of the loop, what is the minimum value for its speed at that point?

FIGURE 6-8 -Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-8. Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal. The coefficient of static friction between block A and the plane is 0.400. What mass should block B have in order to start block A sliding up the ramp?

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 B and C?

FIGURE 6-5 -Two masses, m₁ and m₂, are connected to each other as shown in Figure 6-5. Mass m₁ slides without friction on the table surface. Both masses have acceleration of magnitude a as shown. How does the tension in the string compare to the weight, m₂ g, of mass m₂?

A child pulls a 3.00-kg sled across level ground at constant velocity with a light rope that makes an angle 30.0° above horizontal. The tension in the rope is 5.00 N. Assuming the acceleration of gravity is 9.81 m/s², what is the coefficient of friction between the sled and the ground?

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 30.0° below the horizontal is applied to the box. The coefficient of static friction between the box and the surface is 0.400. What is the force of friction on the box?

What type of acceleration does an object moving with constant speed in a circular path experience?