# Inclined Plane Experiment

INCLINED PLANE EXPERIMENT FOR CLASS 11

Aim

i. To find the downward force along the inclined plane acting on a roller on account of its weight and to study its relationship with the angle of inclination of the inclined plane.

ii. To find the mass of the roller.

Apparatus

Inclined plane, Roller, Weight box, Thread, Weight pan, Metre scale etc

The inclined plane consists of a smooth plane hinged to a base so that it can he set at any desired angle. A heavy metal roller connected to the scale pan by a light inextensible string passing over a frictionless pulley rests on the plane.

Principle

If a roller, under the action of an external force, is in equilibrium on an inclined plane, then

F= mg sinθ

where, m = Mass of the roller

θ = Angle of inclination

F = External force

Therefore, F sinθ

But the external force F = Mg

where, M = Mass of the pan + mass on the pan

Therefore, m = M/sinθ

Procedure

The given inclined plane is placed on a table. The angle of inclination (θ) is adjusted to be 25° using the protractor. The mass of the pan (m1) is measured using a beam balance. One end of a thread passing over a pulley is tied to the pan and the other end to the roller. The roller is placed on the inclined plane. Masses are added in the pan till the roller just moves up. The mass (m2) in the pan is noted. The total mass M = m1 + m2 is calculated. Then the downward force on the roller, F = Mg.

The experiment is repealed for different angle of inclinations.

A graph is plotted with sinθ along the X - axis and downward force (F) along the Y-axis. A straight line graph is obtained.

Mass of the pan, m1 = ______ g

 No Angle of Inclination sinθ Mass of the pan when roller just moves up (m2) Total mass, M = m1+m2 Downward force, F=mg Mass of the roller, m = M/sinθ - degree - g. g. g.wt g. 1 2 3 4 5 6

Mass of the roller (m) = ______ g

Results

i. The downward force along the inclined plane due to gravitational pull of the earth is calculated for different inclinations.

ii. The downward force acting on the roller along the inclined plane is directly proportional to the sine of the angle of inclination.

iii. Mass of the roller =_______ kg.

MODEL VIVA VOCE QUESTIONS AND ANSWERS

1. Define friction.

Friction is an opposing force that comes into play when one body actually moves or even tries to move over the surface of another body.

2. What are the causes of friction?

Interlocking of the elevations and depressions of the surface in contact and the adhesive force between the materials.

3. Name the different types of friction.

(i) Static friction, (ii) Limiting friction, (iii) Sliding friction, (iv) Rolling friction.

4. Define static friction.

Static friction is defined as the opposing force that originates when one body tends to move over the surface of other body, but the real motion has yet not started.

5. Define limiting friction.

Limiting friction is defined as the highest opposing force that originates, when one body is on the verge of moving over the surface of another body.

6. Define sliding friction.

Sliding friction is defined as the opposing force that originates when one body is actually sliding over the surface of another body.

7. What is angle of friction?

It is the angle of inclination of a plane at which a body on it just begins to slide down under gravity.

8. Is rolling friction or sliding friction greater?

Sliding friction is greater than rolling friction.

9. Give the names of some simple machines.

Lever, Pulley, Inclined plane etc

10. What do you understand by an inclined plane?

Inclined plane is one of the simple machines in which a plane surface inclined to the horizontal.