52.) A box slides down a frictionlessplane that makes ang angle of 35 degrees with the horizontal force of half the box’s weight presses the box against the plane. What is the box’s acceleration?

55.) Three objects whose masses are 2.0 kg, 3.0 kg and4.0 kg are joined by strings. The 2.0kg object is pulled upward with a force of 120N. Find the tensions in the strings between the objects.

53.) A 40 kg kangaroo exerts a constant force on the ground in the first 60 cm of her jump, and rises 2.0 m higher. When she carries a baby kangaroo in her pouch, she can rise only 1.8 higher. What is the mass of the baby kangaroo?

61.) Two wooden blocks rest on a wooden table. The coefficient of kinetic friction is 0.30. Find the minimum force needed to move the 3.0-kg block at constant speed in each case.

63.) A ship whose mass is 2.0 x 10^7 rests on launching ways that slope down to the water at an angle of 6 degrees. The ways are greased to reduce the coefficient of kinetic friction to 0.11. Will the ship slide down the ways into the water by itself? If not, find the force needed to launch the ship into the water.

p.s. Thanks to Zandy (suki. hehe.).