World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s^2 .

part a
how much horizontal force f must a sprinter of mass 64 kg exert on the starting blocks to produce this acceleration?
express your answer in newtons using two significant figures.

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?

A. The force exerted by the sprinter must be  9.6 × 10² N.

B. The force that propels the sprinter is exerted by the blocks.

Explanation:

Hi there!

Let´s begin with part B:

The sprinter exerts a force on the blocks and, as a reaction, the blocks exert a force on the sprinter that is of equal magnitude but opposite direction (Newton´s third law). This reaction of the blocks causes the acceleration of the sprinter.

Part A

The force exerted by the blocks can be calculated using Newton´s second law:

F = m · a

Where:

F = exerted force.

m = mass of the object being accelerated.

a = acceleration of the object after applying the force on the object.

F = m · a

F = 64 kg · 15 m/s²

F = 9.6 × 10² N

a.

explanation:

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: