Q1. A worker pushes a wheel-barrow with a force of 40 N over the level distance of 6.0 m. If a frictional force of 24 N acts on wheel-barrow in a direction opposite to that of worker, what total work is done on wheel-barrow?
a) 240 J
b) 216 J
c) 144 J
d) 96 J
e) 75 J
Q2. A satellite is held in orbit through a 2000 N gravitational force. Each and every time the satellite completes an orbit of the circumference 80 000 km, the work done on it by gravity is:
a) 1.6 108 J.
b) 1.6 1011 J.
c) 6.4 1011 J.
d) 0.
e) None of above.
Q3. Which of the given is an example of a non conservative force?
a) Gravity
b) Magnetism
c) Friction
d) Both choices A and B are valid.
e) Both choices A and C are valid.
Q4. The horizontal force of 200 N is applied to the 55 kg cart across the 10 m level surface. If the cart accelerates at 2.0 m/s2, then determine the work done by the force of friction as it acts to retard the motion of cart?
a) -1 100 J
b) -900 J
c) -800 J
d) -700 J
e) -600 J
Q5. An amount of work equivalent to 1.5 J is needed to compress the spring in a spring-gun. Determine the ‘launch speed’ of a 15-g marble?
a) 14 m/s
b) 15 m/s
c) 18 m/s
d) 21 m/s
e) 23 m/s