Answer:
4.2 m
Explanation:
Note: If energy is conserved, i.e no work is done against friction
Work input = work output.
Work output = Force output × distance,
Work input = force input × distance moved moved.
Therefore,
input force×distance moved = output force × distance moved........................Equation 1
Given: input force = 80 N, output force = 240 N, output distance = 1.4 m
Let input distance = d
Substitute into equation 1
80×d = 240×1.4
80d = 336
d = 336/80
d = 4.2 m.
Thus the rope around the pulley must be pulled 4.2 m
Question 4 is true, question 5 is B.
Answer:
No.
Explanation:
The force that two particle experience is inversely proportional to the sqare of the distance, this is:
for a distance D
If we move them so that D is doubled:
= 
Then the force they experience is one fourth of the original.
