Answer:
Explanation:
This figure given is the frequency; 2 times per second represents frequency.
What is frequency?
- It is the number of times per seconds something goes past or around another.
it is expressed as:
Frequency = 
where n is the number of turns
t is the time taken
Therefore, the Barber spinned him 2 times in 1 second.
The period is the inverse of frequency. It is the time taken for a body to go through a point;
Period =
=
s
Answer:
Explanation:
Given
car A had a head start of 
and it starts at x=0 and t=0
Car B has to travel a distance of 
where
is the distance travel by car A in time t
distance travel by car A is

For car B with speed 



Answer:
536,904 J/s
Explanation:
The energy output from motor is the input energy in the machine.
We know that efficiency is percentage energy ouput to energy input, and expressed as

Where n and E represent efficiency and energy respectively, subscripts o and i represent output and input respectively. Since for the machine we have the input energy then the output will be the product of efficiency and input energy
Energy output=0.6*1200 hp=720 hp
Converting hp to J/s we multiply by 745.7
Energy is 720*745.7=536,904 J/s
When object travels with uniform velocity, no force acts on it. hence , yes.