Answer:
0.1 m/s
Explanation:
Please see attached photo for explanation.
Mass of 1st cart (m₁) = 500 g
Initial velocity of 1st cart (u₁) = 0.25 m/s
Mass of 2nd cart (m₂) = 750 g
Initial velocity of 2nd cart (u₂) = 0 m/s
Velocity (v) after collision =.?
m₁u₁ + m₂u₂ = v(m₁ + m₂)
(500 × 0.25) + (750 × 0) = v(500 + 750)
125 + 0 = v(1250)
125 = 1250v
Divide both side by 1250
v = 125 / 1250
v = 0.1 m/s
Thus, the two cart will move with a velocity of 0.1 m/s after collision.
You know that when the displacement is equal to the amplitude (A), the velocity is zero, which implies that the kinetic energy (KE) is zeero, so the total mechanical energy (ME) is the potential energy (PE).
And you know that the potential energy, PE, is [ 1/2 ] k (x^2)
Then, use x = A, to calculate the PE in the point where ME = PE.
ME = PE = [1/2] k (A)^2.
At half of the amplitude, x = A/2 => PE = [ 1/2] k (A/2)^2
=> PE = [1/4] { [1/2]k(A)^2 } = .[1/4] ME
So, if PE is 1/4 of ME, KE is 3/4 of ME.
And the answer is 3/4
