Answer:
8 J and 2 J
Explanation:
Given that,
Mass of the rubber ball, m = 1 kg
Initial speed of the rubber ball, u = 4 m/s (in east)
Final speed of the rubber ball, v = -2 m/s (in west)
We need to find the kinetic energy of the ball before it hits the wall, the kinetic energy of the ball after it bounces off the wall.
Initial kinetic energy,

Final kinetic energy,

So, the initial kinetic energy is 8 J and the final kinetic energy is 2 J.
When object reached the terminal speed then its acceleration is zero
So as per Newton's II law we can say

now in that case we can say that net force is zero so here weight of the object is counter balanced by the drag force when it will reach at terminal speed
so we can write

so here we are given that





so terminal speed will be nearly 2 m/s
I think it would be plum pudding, solid ball, solar system.
Answer:
mass of the composite lump is 10 kg
Explanation:
given data
mass = 4 kg
to find out
mass of composite lump
solution
we know energy is conserved so
so m1 = m2 = m0 that is 4kg
and
E(1) release+ E(2) release = E(1,2) rest
so γ(1)m(1)c² + γ(2)m(2)c² = Mc² ..........................1
that why here
|v(1)| = |v(2)| = 3/5 c ......................2
and
γ = 1 / √(1 − v²/c²) .......................3
put here v = 3 and c is 5
γ = 1 /√(1 − 9/25)
γ = 5/4
so
γ(1) = γ(2) = γ = 5/4
so from equation 1
γ(1)m(1)c² + γ(2)m(2)c² = Mc²
M = 2γm0
M = 2(5/4 )(4)
M = 10 kg
so mass of the composite lump is 10 kg
I believe that the answer is C. Hope this Helps:)))