Power is the rate of work that is done per time. Work is calculated from the product of force and the displacement. So, by using the definition of power and work, we can relate power with force, displacement and the time. We do as follows:
Power = Work / time
Power = Force x displacement / time
Power = 21 N (9 m) / 3 s
Power = 63 J /s = 63 W
It IS <span>PE = (1200 kg)(9.8 m/s²)(42 m) = 493,920 J </span>
As per the question the distance of venus from sun is given as 0.723 AU
We have been asked to calculate the time period of the planet venus.
As per kepler's laws of planetary motion the square of time period of planet is directly proportional to the cube of semi major axis. mathematically

⇒
where is k is the proportionality constant
We may solve this problem by comparing with the time period of the earth . We know that time period of earth is 365.5 days
Hence
The distance of sun from earth is taken as 1 AU i.e the mean distance of earth from sun
Hence 
The distance of venus from sun is 0.723 AU i.e
From keplers law we know that-
⇒
Putting the values mentioned above we get-

⇒
⇒
Hence the time period of venus is 224.388352752710 days
Gamma rays are waves of energy that have no charge. TRUE.
Answer:
magnification will be -0.025
Explanation:
We have given the radius of curvature = 12 cm
And object distance = 3 m
So focal length 
Now for mirror we know that
So 

v = 0.750 m
Now magnification of the mirror is 