Multiple Choice
The three ropes shown in the figure are tied to a steel ring. Two of the ropes are anchored to walls at right angles, and the third rope pulls as shown. If the tension in rope 2 is , what is the mass of the steel ring?
6. Intro to Forces (Dynamics)
Forces in Connected Systems of Objects
Back6. Intro to Forces (Dynamics)
Forces in Connected Systems of Objects
- Multiple ChoiceThree blocks are placed in line on a frictionless table with block B in between blocks A and C. Block A has a mass of , block B has a mass of , and block C has a mass of . A student pushes horizontally on block A with a force of . What is the magnitude of the force of block B on block C?
- Multiple ChoiceThe coefficient of kinetic friction for block A in the figure is 0.2 and the pulley is frictionless. If the mass of block A is , what is the magnitude of its acceleration?
- Multiple ChoiceA toy train consists of an engine, followed by a boxcar, followed by a caboose. All have mass m. When the engine's wheels provide a force F in the forward direction, the train has acceleration a. What is the magnitude of the force of the boxcar on the caboose? Ignore any frictional effects.
- Open Question
(II) A 75-kg petty thief wants to escape from a third-story jail window. Unfortunately, a makeshift rope made of sheets tied together can support a mass of only 62 kg. How might the thief use this 'rope' to escape? Give a quantitative answer.
- Open Question
(II) A window washer pulls herself upward using the bucket–pulley apparatus shown in Fig. 4–40.
<IMAGE>
(b) If she increases this force by 15%, what will her acceleration be? The mass of the person plus the bucket is 78 kg.
- Open Question
(II) One 3.2-kg paint bucket is hanging by a massless cord from another 3.2-kg paint bucket, also hanging by a massless cord, as shown in Fig. 4–41.
<IMAGE>
(a) If the buckets are at rest, what is the tension in each cord?
- Open Question
III) Determine a formula for the magnitude of the force F → exerted on the large block () in Fig. 4–56 so that the mass m_A does not move relative to m_C. Ignore all friction. Assume m_B does not make contact with m_C . <IMAGE>
- Open Question
(III) The two masses shown in Fig. 4–57 are each initially 1.8 m above the ground, and the massless frictionless pulley is 4.8 m above the ground. What maximum height does the lighter object reach after the system is released? [Hint: First determine the acceleration of the lighter mass and then its velocity at the moment the heavier one hits the ground. This is its 'launch' speed. Assume the mass doesn't hit the pulley or the ceiling. Ignore the mass of the cord.]
<IMAGE>
- Open Question
A coffee cup on the horizontal dashboard of a car slides forward when the driver decelerates from 45 km/h to rest in 3.5 s or less, but not if she decelerates in a longer time. What is the coefficient of static friction between the cup and the dash? Assume the road and the dashboard are level (horizontal).
- Open QuestionA 500 kg air conditioner sits on the flat roof of a building. The coefficient of static friction between the roof and the air conditioner is 0.90. A massless rope attached to the air conditioner passes over a massless, frictionless pulley at the edge of the roof. In an effort to drag the air conditioner to the edge of the roof, four 100 kg students hang from the free end of the rope, but the air conditioner refuses to budge. What is the magnitude of the rope tension at the point where it is attached to the air conditioner?
- Open QuestionFIGURE EX7.17 shows two 1.0 kg blocks connected by a rope. A second rope hangs beneath the lower block. Both ropes have a mass of 250 g. The entire assembly is accelerated upward at 3.0 m/s^2 by force F. (b) What is the tension at the top end of rope 1?
- Open QuestionA rope of length L and mass m is suspended from the ceiling. Find an expression for the tension in the rope at position y, measured upward from the free end of the rope.
- Open QuestionA 2.0-m-long, 500 g rope pulls a 10 kg block of ice across a horizontal, frictionless surface. The block accelerates at 2.0 m/s^2. How much force pulls forward on (b) the rope? Assume that the rope is perfectly horizontal.
- Open Question
A 1.5-kg block rests on top of a 7.5-kg block (Fig. 4–70). The cord and pulley have negligible mass, and there is no significant friction anywhere. <IMAGE>
(b) What is the tension in the connecting cord?