Answer:
Speed, u = 29.4 m/s
Explanation:
Given that, A ball thrown straight up climbs for 3.0 sec before falling, t = 3 s
Let u is speed with which the ball is thrown up. When the ball falls, v = 0
Using first equation of motion as :
v = u + at
Here, a = -g
So, u = g × t

u = 29.4 m/s
So, the speed with which the ball was thrown is 29.4 m/s. Hence, this is the required solution.
Due to the principle of conservation of energy, the work done by the engine to move the scooter converts into kinetic energy of the scooter:

where M is the combined mass of scooter and rider, and v is the velocity of the scooter. Therefore, we can find the velocity as:
If the force is in the right range ... not too strong and not too
weak ... then a bathroom scale can be used to measure it.
If the force is huge, then you'd need a truck scale.
If the force is small, then you'd need a laboratory balance.
Answer:
Height, h = 10.20 meters
Explanation:
It is given that,
Mass of the object, m = 3 kg
Energy of object, E = 300 J
Let it will moved to a height of h. The energy possessed by it is called gravitational potential energy. It is given by :



h = 10.20 meters
So, the object will move to height of 10.20 meters. Hence, this is the required solution.