Answer:
P=9.58 W
Explanation:
According to Newton's second law, and assuming friction force as zero:

The acceleration is given by:

So the force exerted by the motor is:

The work done by the motor is given by:


And finally, the power is given by:

Answer:
Explanation:
Given
length of window 
time Frame for which rock can be seen is 
Suppose h is height above which rock is dropped
Time taken to cover 
so using equation of motion

where y=displacement
u=initial velocity
a=acceleration
t=time
time taken to travel h is

Subtract 1 and 2 we get


and from equation 
so 

and 
so 



substitute the value of
in equation 2


Nacl is the answer hahahahaah ha
Period, T, is 1/frequency
T = 1/340 = 2.941ms