IB Physics-Theme-A2- A student uses a load to pull a box up a ramp inclined

A student uses a load to pull a box up a ramp inclined at 30°. A string of constant length and negligible mass connects the box to the load that falls vertically. The string passes over a pulley that runs on a frictionless axle. Friction acts between the base of the box and the ramp. Air resistance is negligible. The load has a mass of 3.5 kg and is initially 0.95 m above the floor. The mass of the box is
1.5 kg. The load is released and accelerates downwards.
(a) Outline two differences between the momentum of the box and the momentum of the load at the same instant .

(b) The vertical acceleration of the load downwards is 2.4 m s−2
.Calculate the tension in the string.
(c.i) Show that the speed of the load when it hits the floor is about 2.1 m s−1
The radius of the pulley is 2.5 cm. Calculate the angular speed of rotation of the pulley as the load hits the floor. State your answer to an appropriate number of significant figuer.
(d) After the load has hit the floor, the box travels a further 0.35 m along the ramp before coming to rest. Determine the average frictional force between the box and the surface of the ramp.
(e) The student then makes the ramp horizontal and applies a constant horizontal force to the box. The force is just large enough to start the box moving. The force continues to be applied after the box begins to move.
Explain, with reference to the frictional force acting, why the box accelerates once it has started to move.
Theme A- A space,time and motion

[blindy]

Miss for question e, how did you know which direction is the component - mg sin(theta) is acting on.