Answer:
External force on him will be 112 N
Explanation:
We have given the mass of the sprinter m =70 kg
Acceleration of the sprinter 
We have to find the net external force
According to second law of motion force = mass ×acceleration
Force is dependent on the mass and acceleration
So 
So external force will be 112 N
It is simply called Entropy.
Answer:
D, using a spring scale to exert a force on the block. Measure the acceleration of the block and the applied force
Explanation:
For this you would use the net force equation acceleration=net force * mass however you will want to isolate mass so it would be acceleration/ net force to get mass. Then process of elimination comes to play.
The maximum speed of the object under simple harmonic motion is 0.786 m/s.
The given parameters:
- Position of the particle, y = 0.5m sin(πt/2)
<h3>Wave equation for
simple harmonic motion;</h3>
y = A sin(ωt + Ф)
where;
- A is the amplitude = 0.5 m
- ω is the angular speed = π/2
The maximum speed of the object is calculated as follows;

Thus, the maximum speed of the object under simple harmonic motion is 0.786 m/s.
Learn more about simple harmonic motion here: brainly.com/question/17315536
L = r x p = rmv = mr²ω
L = 0.25 x 0.75² x 12.5 = 1.758