It would need to be over 20 because if the load of the Pulley E is 20 and the effort is 20, then they will be equal and the Pulley would not move, so your answer is at least 20
Answer:
the decrease in energy is due to a transformational in internal energy of the body in the rebound.
Explanation:
For this exercise we can calculate the initial and final mechanical energy
Em₀ = U = m g y₁
= U = m g y₂
we look for the variation of the energy
ΔEm = Em_{f} - Em₀
ΔEm = m g (y_{f} -y₀)
ΔEm = m g (0.86 -1.2)
ΔEm = -3.332 m
We can see that there is a decrease in mechanical energy, this is transformed into internal energy of the ball during the impact with the ground, this energy can be formed by several factors such as a part of the friction with the surface, an increase in body temperature or a deformation of the body; there may be a contribution from several of these factors.
In conclusion the decrease in energy is due to a transformational in internal energy of the body in the rebound.
Explanation:
It is given that,
The acceleration of a particle,
(negative as the particle is decelerating)
Initial distance, x₁ = 20 m
Initial time, t₁ = 4 s
New distance x₂ = 4 m
Velocity, v = 10 m/s
(A) Calculating initial distance using second equation of motion as :


u = 21 m/s
When velocity of the particle is zero, time taken is t (say). Using first equation of motion as :


t = 2.62 seconds
So, the velocity of the particle is zero at t = 2.62 seconds.
(B) Velocity at t = 11 s

v = 13 m/s
Total distance covered at t = 11 s. The overall path travelled by the particle during its entire journey is called total distance covered.


d = 132.48 m
So, the distance travelled by the particle at t = 11 seconds is 132.48 meters.
Answer:

Explanation:
Given:

As we know that
Force=Mass * Acceleration
Putting the value of mass and Acceleration we get ,


Therefore Net force is :