Question

a. 5. A child pulls a sled up a snow-covered hill. The child does 405 J of work on the sled. If the child walks 15 m up the hill, how large of a force must the child exert?

b.6. How much work is done on a small car if a 3150 N force is exerted to move it
75.5 m to the side of the road?

Answer 1

Answer:

(a) The force must be 27 Newton.

(b) The work done on the small car is 2.3×10⁵Joules.

Explanation:

First, let's see the relationship between force and work done which is given as;

$\mathrm{W=F.x}$                    (1)

Where,

W=work done on the body

F=force acting on the body

x=distance through which the body is displaced

CASE (a): Work done=405Joules

The work done by the child is(W) =405 Joules

The distance covered by the child in walking up the hill(x)=15 m

Inserting the values of "W" and "x" in equation (1) we get;

$\mathrm{405=F\times 15}$

$\mathrm{F=\frac{405}{15}=27 \ Newton }$        (2)

The force must be 27 Newton.

CASE (b): The force exerted is =3150N

The force exerted on the car=3150N

The distance required to move(x)=75.5m

Inserting the values of "F" and "x" in equation (1) we get;

$\mathrm{W=3150\times 75.5}$

$\mathrm{W=237825\ Joules}$

$\mathrm{W\approx 2.3\times 10^5\ Joules}$

The work done on the small car is 2.3×10⁵Joules.

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Answer 2

Answer:

The force exerted by by the child is 27 Newton.

The work done by small car is 2.3x 10^5.

Explanation:

Concept: Work done = Force x displacement

W = F. x

Where , W is the work done

F is the force acting

x is the displacement

Case (a)

Given: Work done = 405 J

Displacement= 15 m

Find: Force(F) exerted by child.

Step by step explanation

Work done = Force x displacement

W = F. x

405J = F x 15

Force(F) = 405/15

Force (F) = 27 Newton

The force exerted by by the child is 27 Newton.

Case (b)

Given: Force (F) = 3150 N

Displacement (x) = 75.5m

Find: Work done on small car.

Step by step explanation

Work done = Force x displacement

W = F. x

W= 3150x 75.5

W= 237825J

W= 2.3x 10^5

Hence , the work done by small car is 2.3x 10^5.

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