1. An object of mass 2 kg is sliding with a constant velocity of 4 m/ s on a frictionless horizontal table. The force required to keep the object moving with the same velocity is
(a) 32 N (b) 0 N (c) 2 N (d) 8 N (b]
2. Rocket works on the principle of conservation of
(a) mass (b) energy (c) momentum (d) velocity [c]
3. A car is moving at 45 km/hr.A constant force acts on the car for 10 sc .So that it's velocity becomes 63 km/hr .The distance travelled by car during this interval of 10 sec is :
a) 100 m b) 150 m c) 200 m d) 50 m [b]
What is the definition of balanced and unbalanced force?
When two equal forces acting on an object in opposite directions called balanced force. When something does not move the forces are balanced, e.g. Gravity pulls a table down but that table is pushed up by the floor or the ground it stands on so doesn’t’ move.
An Unbalanced force is needed for something to change movement or change direction, e.g. aseesaw moving up and down because the forces are not equal.
Net force: - The sum of all the forces acting on a body is known as net force.
Difference between Balanced force and unbalanced force.
Balanced force:- If net force on a body is zero it is called balanced force. Balanced forces do not cause a change in motion. They are equal in magnitude and opposite in direction. Therefore, the resultant of these forces will be zero.
Example: Two persons pushing a box with the same force in opposite directions.
Unbalanced forces:- If net force on a body is non-zero it is called unbalanced force.
Forces whose resultant is not equal to zero are called unbalanced forces. For example: An arm wrestling competition among a strong person and a weak one. The resultant force will be in the direction of the force applied by the strong person.
What Is Inertia
By Newton's law we know that ,a body at rest will remain at rest and a body in motion will continue in a straight line unless it is compelled by an external force.This tendency of a body is called inertia.So we can say that 'Inertia is that property of a body due to which it resists a change in its state of rest or of uniform motion.'
When the brakes are applied to the bike the back seater moves forward why?
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