Physics Quiz on Machines

If a heavy barrel is rolled up a plane inclined at 30° to the horizontal. its velocity ratio will be?

• 3.0

• 3.1

• 3.2

• 2.0

A machine of velocity ratio 6 requires an effort of 400 N to raise a load of 800 N through I m. Find the efficiency of the machine

• 55. 6 %

• 50.0%

• 33.3%

• 22.2%

The efficiency of the pulley system shown above is 80%. find the effort E required to lift the load of 1200N

• 275N

• 325N

• 375N

• 573N

fig 4 represents a block-and-tackle pulley system on which an effort of W newtons supports a load of 120.0N if the efficiency of the system is 40% then the value of W is

• 28.0N

• 48.0N

• 50.0N

• 288.0N

The diagram shown represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is 40, then the value of W is?

• 28.0

• 48.0N

• 233.0N

• 50.0N

Which of the following machines does not apply the lever principle?

• Claw hammer

• Wheelbarrow

• Single pulley

• sugar tong

The efficiency of a wheel and axle is 100% and the ratio of their radii is 5:1. calculate the effort required to lift a load of mass 20kg using this machine, [g = 10 m s−2−2]

• 20N

• 25N

• 40N

• 100N

Which of these is a second-class lever?

• sugar tongs

• claw hammer

• plier

• wheelbarrow

A machine has a velocity ratio of 5 and 80% efficient. What effort would be needed to lift a load of 2000N with the aid of this machine?

• 500N

• 400N

• 650N

• 300N

A Machine with V.R of 5 requires 1000J of work to raise a load of 500N through a vertical distance of 1.5m. Find the efficiency and M.A of the machine?

• 85%, 3.75

• 90%, 2.75

• 85%, 4.75

• 75%, 3.75