A classmate describes a trick he saw using Newton's cradle. He pulled back two of the cradle balls and let them swing down to strike the line of other balls. He then saw three balls swing away on the other side with the same speed as the first two balls. The three balls only rose to 2/3 of the original height. Explain what must be wrong with your classmate's
description.

what was the acceleration of the 2 kg cart?

⇒ 16.0 cm/s2

what was the acceleration of the 4 kg cart?

⇒ 8.1 cm/s2

what was the acceleration of the 6 kg cart?

⇒ 5.3 cm/s2

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards

option number c is the right answer.