Question

Anna pushes her little brother on his sled with a force of 300N for 750m. How much work is this if the force of friction acting on the sled is (a) 200 N, (b) 300 N​

Answer 1

The applied force by the girl on the sled of her little brother is

F

=

300

N

.

The displacement in the sled of her...

Answer 2

Work done is 75  kJ if force of friction is 200N and no work done if  force of friction is 300 N

Given:

• Anna pushes her little brother on his sled with a force of 300N for 750m.

To Find:

• Work done if  the force of friction acting on the sled is
• a) 200 N
• b) 300 N

Solution:

• Work Done = Net Force x Displacement

Net Force = Force Applied - Force Against

In this case:

Net Force = Force Applied - Frictional Force

Step 1:

Find net force when force of friction is 200 N

Net Force =  300 - 200  = 100 N

Step 2:

Calculate the work done

Work Done = 100 x 750   = 75000 J = 75 kJ

Step 3:

Find net force when force of friction is 300 N

Net Force =  300 - 300  =  0 N

Step 4:

Calculate the work done

Work Done =  0 x 750   =  0 J

Means no work done

Work done is 75  kJ if force of friction is 200N and no work done if  force of friction is 300 N