Question

World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s² .

A) How much horizontal force F must a sprinter of mass 60 kg exert on the starting blocks to produce this acceleration?
Express your answer in newtons using two significant figures.
B) Which body exerts the force that propels the sprinter, the blocks or the sprinter?

Answer 1

To produce an acceleration of 15 m/s², a sprinter with a mass of 60 kg must exert a horizontal force of 900 N on the starting blocks. The sprinter exerts the force that propels them forward, not the starting blocks.

Step-by-step explanation:

In order to calculate the horizontal force exerted by a sprinter of mass 60 kg to produce an acceleration of 15 m/s², we can use Newton's second law of motion: F = m * a. Here, the mass is 60 kg and the acceleration is 15 m/s². Plugging these values into the equation, we get F = 60 kg * 15 m/s² = 900 N. Therefore, the sprinter must exert a horizontal force of 900 newtons on the starting blocks.

The sprinter exerts the force that propels them forward, not the starting blocks. The blocks only provide a surface for the sprinter to push against. When the sprinter applies a force against the starting blocks, an equal and opposite force is exerted by the sprinter's feet, propelling them forward.