Exam 4: Forces and Motion I: Newtons Laws

In a crash test, the strapped-in 75-kg dummy moves a distance of 0.80 m when the test car is slammed straight into a wall at 11.2 m/s ~25 mph). The average force acting on the dummy during the collision is how many times his own weight?

Rachel has been reading her physics book. She takes her weighing scales into an elevator and stands on them. If her normal weight is 690 N 155 lbs) and the elevator moves upward at 0.25 g and then down at 0.25 g, what is the difference between the up and down scale readings?

A lamp with a mass m is suspended from the ceiling by two cords as shown. The ratio of the magnitude of the vertical component of the tension in to that in is

A physical quantity that is sometimes described as the measure of the resistance of a body to a change in its motion is

A lamp with a mass m = 42.6 kg is hanging from wires as shown. The magnitude of tension in the vertical wire is

Two masses m₁ and m₂ with m₂ > m₁) are connected by a massless rope hung over a frictionless light pulley. If the masses are released then the acceleration of m₂ in the downward direction is given by

A 44.5-N weight is hung on a spring scale, and the scale is hung on a string. The string is lowered at a rate such that the entire assembly has a downward acceleration of 4.90 m/s². The scale reads

A shopper steps on an escalator moving downward at a constant speed toward the bargain basement in a large department store. On his way down, the normal force exerted on him by the step of the escalator is

You are riding an elevator that is accelerating upward at 2.20 m/s². You have a spring balance that is accurately calibrated in newtons. When you hang a mass of 10.0 kg on the balance, the reading of the balance is

A third force is applied on the object so that the net force on the object is zero. Which force vector best represents the third force?

A frictionless pulley of negligible mass is hung from the ceiling using a rope, also of negligible mass. Two masses, m₁ and m₂ m₁ < m₂) are connected to the rope over the pulley. The masses are free to drop. The magnitude of the tension T_top is ______ the sum of the weights W₁ = m₁g and W₂ = m₂g.

A body is sent out in space. Which of the following statements is true of this body as it moves away from Earth?

A force accelerates a body of mass M. A second body requires half as much force to produce twice the acceleration. What is the mass of the second body?