Question

Starting from rest, a person pushes a 20 kg box with a constant force of 350N calculate the speed of the box after it is pushed for 2.5s

Answer 1

Given:

The mass of the box, m=20 kg

The initial velocity of the box, u=0 m/s

The force applied on the box, F=350 N

The time period, t=2.5 s

To find:

The final speed of the box.

Step-by-step explanation:

The acceleration of an object is the time rate of change of the velocity of the object.

Thus the acceleration of the box due to the applied force is given by the equation,

`a=(v-u)/(t)\text{ }\to\text{ \lparen i\rparen}`

Where v is the final speed of the box.

From Newton's second law, the force applied to the box is given by,

`F=ma`

On substituting the equation (i) in the above equation,

`F=m*(v-u)/(t)`

On substituting the known values in the above equation,

`\begin{gathered} 350=20*(v-0)/(2.5) \\ \implies v=(350*2.5)/(20) \\ =43.75\text{ m/s} \end{gathered}`

Final answer:

Thus the final speed of the box is 43.75 m/s