F n e t = m a . World-class sprinters can accelerate out of the starting blocks

Question

Fnet=ma.

World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s2. Part A How much horizontal force F must a sprinter of mass 64kgexert on the starting blocks to produce this acceleration? Express your answer in newtons using two significant figures. F= N SubmitHintsMy AnswersGive UpReview Part Hint:According to Newton's 2nd law of motion, if a net external force Fnet acts on a body, the body accelerates, and the net force is equal to the mass m of the body times the acceleration a of the body:

Fnet=ma.

Part B Which body exerts the force that propels the sprinter, the blocks or the sprinter? Which body exerts the force that propels the sprinter, the blocks or the sprinter? the blocks the sprinter SubmitHintsMy Answers Hint:To start moving forward, sprinters push backward on the starting blocks with their feet. Newton's 3rd law tells you that the blocks exert a force on the sprinter of the same magnitude, but opposite in direction.

Explanation / Answer

We know that

Force (F) = mass (m ) * acceleration (a)

Given a= 15 m/sec^2

m= 64 Kg

F = 64 *15 = 960 N

B) According to Newton's third law,

Every action has equal and opposite reaction.

So Sprinter pulls blocks forward,

While Blocks propells sprints backwards.

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