Question

When a block of wood of 2kg is pushed along a horizontal fat sureface of bench ,the force of friction is 4N .when a force of 10N, It moves with a constant

Answer 1

Answer:

Work done by applied force on the block=F×s

=F×s

=40×2

=80J

Work done gravitational force on the object=mg×s

=mg(−s) (-ve sign as direction of displacement and force is opposite here)

=2×10×−2

=−40J

Explanation:

May this help you

Answer 2

Given :

Mass of the block = 2kg

Applied force = 10N

Force of friction = 4N

To Find :

Acceleration of the block.

Solution :

❖ In this case force of friction opposes the motion of block as it acts in the opposite direction.

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» As per newton's second law of motion, force is measured as the product of mass and acceleration.

• It is a polar vector quantity as it has a point of application.
• SI unit : N

First of all we have to calculate net force acts on the block.

➙ Fn = F - f

• Fn denotes net force
• F denotes force
• f denotes frictional force

➙ Fn = F (→) - f (←)

➙ Fn = 10 - 4

➙ Fn = 6 N

We know that, Fn = m × a

» m denotes mass

» a denotes acceleration

By substituting the given values;

➠ 6 = 2 × a

➠ a = 6/2

➠ a = 3 m/s²