UNIVERSITI TUNKU ABDUL RAHMAN
|Centre |: Centre for Foundation Studies (CFS) |Unit Code |: FHSC1014 |
|Course |: Foundation in Science |Unit Title |: Mechanics |
|Year/ Trimester |: Year 1 / Trimester 2 & 3 |Lecturer |: Kevin Chin |
|Session |: 201605 | | |
Additional Tutorial 4: Work and Energy.
1. A push of 120 N is applied along ...view middle of the document...
The block of mass m2 is attached to a spring of force constant k and m1. m2. If the system is released from rest, and the spring is initially not stretched or compressed, find an expression for the maximum displacement d of m2. [d = 2g(m1- m2)/k]
7. Tarzan swings on a 30.0 m long vine initially inclined at an angle of 37.0° with the vertical. What is his speed at the bottom of the swing (a) if he starts from rest? (b) If he pushes off with a speed of 4.00 m/s? [(a) 10.9 m/s, (b) 11.6 m/s]
8. Two objects are connected by a light string passing over a light frictionless pulley as shown in figure. The object of mass 5.50 kg is released from rest. (a) Using the principle of conservation of energy, determine the speed of the 3.20 kg object just as the 5.50 kg object hits the ground. (b) Find the maximum height to which the 3.20 kg object rises. [(a) 5.09 m/s, (b) 6.32 m]
9. A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope inclined at 20.0° above the horizontal. The sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.500.
(a) What is the tension in the rope? [79.4 N]
(b) How much work is done by the rope on the sledge? [1.49×103 J]
(c) What is the mechanical energy lost due to friction? [-1.49×103 J]
10. A crate of mass 10.0 kg is pulled up a rough incline with an initial speed of 1.50 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 20.0° with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 5.00 m.
(a) How much work is done by gravity? [-168 J]
(b) How much mechanical energy is lost due to friction? [-184 J]
(c) How much work is done by the 100 N force? [500 J]
(d) What is the change in kinetic energy of the crate? [148 J]
(e) What is the speed of the crate after being pulled 5.00 m? [5.64 m/s]
11. Two blocks, A and B (with mass 50 kg and 100 kg, respectively), are connected by a string, as shown in figure. The pulley is frictionless and of negligible mass. The coefficient of kinetic...