Match the following: a. An apple falls down from a tree i. Magnetic force b. A football rolls on the ground ii. Muscular force c. A nail clings to a magnet iii. Electrostatic force d. A bullock pulls a cart iv. Mechanical force e. Bits of paper attracted to a charged ruler v. Frictional force f. Force employed by the machine parts vi. Gravitational force

a. An apple falls down from a tree - vi. Gravitational force The earth pulls all objects towards it. This is called gravity. b. A football rolls on the ground - v. Frictional force The direction of this force is opposite to the direction of motion. Such force is called frictional force. c. A nail clings to a magnet - i. Magnetic force It is a force that causes the magnets to attract certain objects like metals. d. A bullock pulls a cart - ii. Muscular force Force applied by the muscles of our body is called a muscular force. e. Bits of paper attracted to a charged ruler - iii. Electrostatic force The electrostatic force is an attractive and repulsive force between particles are caused due to their electric charges. f. Force employed by the machine parts - iv. Mechanical force Force applied by the machines is called mechanical force. It is a type of contact force. a. An apple falls down from a tree vi. Gravitational force b. A football rolls on the ground v. Frictional force c. A nail clings to a magnet i. Magnetic force d. A bullock pulls a cart ii. Muscular force e. Bits of paper attracted to a charged ruler iii. Electrostatic force f. Force employed by the machine parts iv. Mechanical force

Observe the forces acting on the box A. Box A will move towards which direction? Why?

Forces are acting in the opposite direction. The force acting towards left side is greater than the force acting towards right side. Hence the resultant force will be the difference between the two i.e. 5 N acting towards left. So the box will move towards left.

Observe the forces acting on the boxes B. Box B will _____.

The resultant force is the net sum of all the forces acting on the body. The forces acting on the left side are equal and opposite to the force acting on the right side. Hence the resultant force is zero. Therefore, box B will not move.

Observe the forces acting on the box C. Box C will move towards _____.

If two forces act on an object in the same direction, the net force is equal to the sum of the two forces i.e the net force of box C is 17 N . Both the forces are acting towards the right side so box C move towards the right direction.

Observe the forces acting on the boxes A, B, and C. Net forces on Boxes A, B and C are _____, _____ and _____.

Given: Force acting towards left side= 8 N Force acting towards right side= 3 N Net force will be the subtraction of forces, as forces are acting in the opposite direction. Net force on Box A = 8 N - 3 N = 5 N Given: Both the forces acting towards the centre of the box B. Net force will be subtraction of forces as forces are acting in opposite direction. Here net force is zero. Net force= ( 4 N + 3 N ) - 7 N = 0 Given: Both the forces are acting on the same side. Net force will be addition of forces as the forces are acting in one direction. Net force= ( 8 N + 6 N ) + 3 N = 17 N

E M B I B E

Expanded Universal Science>Chapter 11 - Force and Pressure>TRACK YOUR PROGRESS>Q 1

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Force is a (vector/ scalar) quantity.

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Important Questions on Force and Pressure

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Expanded Universal Science>Chapter 11 - Force and Pressure>TRACK YOUR PROGRESS>Q 2

Match the following:

a. An apple falls down from a tree	i. Magnetic force
b. A football rolls on the ground	ii. Muscular force
c. A nail clings to a magnet	iii. Electrostatic force
d. A bullock pulls a cart	iv. Mechanical force
e. Bits of paper attracted to a charged ruler	v. Frictional force
f. Force employed by the machine parts	vi. Gravitational force