Question

In a metre scale in equilibrium, pivot at 40cm, 10kg at 25cm, 5kg at 60cm. Find mass of the scale.​

Answer 1

Answer:

Answer

Correct option is

B

0.06 kg

As the scale is uniform, so the weight will be balanced at mid point i.e. 50 cm of the scale.

Let, M be the mass of the meter scale.

Using principle of moments, for equilibrium, sum of moment of force on left side of knife edge is equal to sum of moment of force on right side.

So, (70−50)Mg=(94−70)0.05g (as moment of force = force × perpendicular distance from fulcrum)

or M=0.06kg

Answer 2



AP Physics 1 : Torque

Study concepts, example questions & explanations for AP Physics 1

Example Questions

AP Physics 1 Help » Newtonian Mechanics » Circular, Rotational, and Harmonic Motion » Circular and Rotational Motion » Torque

Torque : Example Question #1

A bolt connecting the main and rear frame of a mountain bike requires a torque of 15N⋅m to tighten. If you are capable of applying 40N of force to a wrench in any given direction, what is the minimum length of the wrench that will result in the required torque?

Possible Answers:

0.84m

0.21m

0.38m

0.60m

0.33m

Correct answer:

0.38m

Explanation:

The minimum length of the wrench will assume that the maximum force is applied at an angle of 90∘. Therefore, we can use the simplified expression for torque:

T=F⋅r

Here, r is the length of the wrench.

Rearranging for length and plugging in our values, we get:

r=TF=15N⋅m40N=0.375m