Question

2. A block of mass 3.0 kg rests on an inclined planw that makes an angle with the horizontal of 25...(pic)

4. A man weighs an apple with a string scale attached to the ceiling of an elevator...(pic)

9. A diver weighing 600 N drops from a board h meters above the surface of the water...(pic)

10. A block with a mass of 5.0 kg is attached to a horizontal spring with a spring constant 300 N/m...(pic)

2. A block of mass 3.0 kg rests on an inclined plane that makes an angle with the horizontal of 25. If the maximum friction force between the block and the surface is 11.6 N, find the coefficient of static friction. 4. A man weighs an apple with a spring scale attached to the ceiling of an elevator. At rest, the scale reads 0.9 N. If the scale then reads 1.5 N when the elevator accelerates upwards at a constant rate, find this acceleration. 9. A diver weighing 600 N drops from a board h meters above the surface of the water. If the speed of the diver when she is h/4 meters above the surface is 5.0 m/s, find h. 10. A block with mass 5.0 kg is attached to a horizontal spring with spring constant 300.0 N/m. If the block is initially pulled out a distance x cm and then released, and its velocity when it first reaches the equilibrium point is 0.51 m/s, find x.

Answer 1

(2) The forces acting on the block is shown below: 1 mg sin 25° mg mg cos 25° 250 Balance the forces acting on the block along the vertical direction is as follows: N = mg cos 25° The expression for the static frictional force is, f. = 4.N 11.6 N (3 kg)(9.8 m/s) cos (250) = 0.43 Given that at rest the scale reads the weight of the apple is, W =0.9 N The expression for the weight of the object is, W = mg m =- 0.9 N 9.8 m/s2 = 0.092 kg When the elevator accelerates upwards the scale reads the weight of the apple as, W' =1.5 N Balance the forces when the elevator accelerates upwards as follows: W'=W + ma 1.5 N=0.9 N+(0.092 kg) a a=6.52 m/s