Answer:
20 Joules
Explanation:
Work is done whenever a force moves a body through a certain distance in the direction of the force. So, work done is the product of force and distance moved.
Therefore, we have;
Work done = Force x distance
i.e Wd = Fs
Given that: F = 20 N and s = 1 m, then;
Wd = 20 N x 1 m
= 20 Nm
The work done by the father is 20 Joules(Nm).
Answer:
T = 764.41 N
Explanation:
In this case the tension of the string is determined by the centripetal force. The formula to calculate the centripetal force is given by:
(1)
m: mass object = 2.3 kg
r: radius of the circular orbit = 0.034 m
v: tangential speed of the object
However, it is necessary to calculate the velocity v first. To find v you use the formula for the kinetic energy:

You have the value of the kinetic energy (13.0 J), then, you replace the values of K and m, and solve for v^2:

you replace this value of v in the equation (1). Also, you replace the values of r and m:

hence, the tension in the string must be T = Fc = 764.41 N
the rate of work done or doing work is usually measured by the power of a machine .
Answer:
c
Explanation:
it's the only one that makes sense