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A contestant in a winter sporting event pushes a 45.0-kg block of ice across a frozen lake as shown in Figure 5.23(a). (a) Calculate the minimum force F he must exert to get the block moving. (b) What is the magnitude of its acceleration once it starts to move, if that force is maintained?

 

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Analyn Tolentino
Analyn TolentinoLv10
24 Jan 2021

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Related textbook solutions

Physics: Principles with Applications
7th Edition, 2013
Giancoli
ISBN: 9780321625922

Related questions

A block of mass m lies on a horizontal table. The coefficient of static friction between the block and the table is μs. The coefficient of kinetic friction is μk, with μk<μs.

Part A

If the block is at rest (and the only forces acting on the block are the force due to gravity and the normal force from the table), what is the magnitude of the force due to friction?

Part B

Suppose you want to move the block, but you want to push it with the least force possible to get it moving. With what force F must you be pushing the block just before the block begins to move?

Express the magnitude of F in terms of some or all the variables μs,μk, and m, as well as the acceleration due to gravity g.

Part C

Suppose you push horizontally with half the force needed to just make the block move. What is the magnitude of the friction force?

Express your answer in terms of some or all of the variables μs, μk, and m, as well as the acceleration due to gravity g.

Part D

Suppose you push horizontally with precisely enough force to make the block start to move, and you continue to apply the same amount of force even after it starts moving. Find the acceleration a of the block after it begins to move.

Express your answer in terms of some or all of the variables μs, μk, and m, as well as the acceleration due to gravity g.



1.A 4.00-kg block rests between the floor and a3.00-kg block asshown in the Figure. The 3.00-kg block is tied toa wall by ahorizontal rope. If the coefficient of static frictionis 0.800between each pair of surfaces in contact:

a) Draw free-body diagrams for the two boxesidentifying all ofthe forces acting on each of themasses.

b) Calculate the minimum force F that mustbe appliedhorizontally to the 4.00- kg block to make itmove?

c) What will be the tension in the rope underthe condition in(b).

2.Two skaters, a man and a woman,are standing on ice. Neglectany friction between the skate bladesand the ice. The woman pusheson the man with a certain force thatis parallel to the ground.

a) Must the man accelerate underthe action of this force? If so,what three factors determine themagnitude and direction of hisacceleration?

b) Is there a corresponding forceexerted on the woman? If so,where does itoriginate?

c) Is this force on the womanrelated to the magnitude anddirection of the force the womanexerts on the man? If so, how?

d) The mass of the man is 74 kgand that of the woman is 50 kg.The woman pushes on the man with aforce of 45 N due east. Determinethe acceleration (magnitude anddirection) of (i) the man and (ii)the woman

5.29 - A 45.0-kg crate of tools rests on a horizontal floor. You exert a gradually increasing horizontal push on it, and the crate just begins to move when your force exceeds 313 N. Then you must reduce your push to 208 N to keep it moving at a steady 25.0 cm/s. (a) What are the coefficients of static and kinetic fric- tion between the crate and the floor? (b) What push must you exert to give it an acceleration of 1.10 m/s2? (C) Suppose you were per- forming the same experiment on the moon, where the acceleration due to gravity is 1.62 m/s. 1) What magnitude push would cause it to move? (ii) What would its acceleration be if you maintained the push in part (b)?

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