Hello I would appreciate help on these questions (7, 8 and 9 all parts) thank you so much!

7. [-/3 Points] DETAILS SERPSE10 8.2.P.003. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER A block of mass m = 5.40 kg is released from rest from point @ and slides on the frictionless track shown in the figure below. (Let ha = 7.30 m.) 3.20 m 2.00 m (a) Determine the block's speed at points B and C. VR = m/s m/s b) Determine the net work done by the gravitational force on the block as it moves from point @ to point @. Need Help? Read It Watch It 8. [-/1 Points] DETAILS SERPSE10 8.2.P.006. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER The system shown in the figure below consists of a light, inextensible cord, light, frictionless pulleys, and blocks of equal mass. Notice that block B is attached to one of the pulleys. The system is initially held at rest so that the blocks are at the same height above the ground. The blocks are then released. Find the speed of block A at the moment the vertical separation of the blocks is h. (Use any variable or symbol stated above along with the following as necessary: g.) A B Need Help? Read It 9. [-/2 Points] DETAILS SERPSE10 8.3.OP.007. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER A box is given a push across a horizontal surface. The box has a mass m, the push gives it an initial speed of vy, and the coefficient of kinetic friction between the box and the surface is "k. (a) Use energy considerations to find an expression for the distance the box moves before it stops. (Use any variable or symbol stated above along with the following as necessary: g.) d = (b) What If? If the initial speed of the box is increased by a factor of 4, determine an expression for the new distance dnew the box slides in terms of the old distance d. Need Help? Read It