Question

a 5.0 kg object is moved at 16m/s when a 2 N force is applied opposite to the direction of the objects motion causing it to slow down to 12 m/a.How long was this force applied?

Answer 1

`\frak{\pink{Given}}\begin{cases}\textsf{ Mass of an object is 5kg.}\\\textsf{ A force of 2N is applied}\\\textsf{ It slows down to 12m/s from 16m/s.} \end{cases}`

And we need to find out the time during which the force was applied. As we know that the rate of change of momentum is directly proportional to the applied force in the dirⁿ of the force , where the value of constant is 1. So ,

`\longrightarrow` F = ∆p/t

`\longrightarrow` F = m (v - u)/t

• Here the force will be negative since the direction of motion is opposite to the direction of the force .

`\longrightarrow` -2N = 5kg ( 12-16)/t

`\longrightarrow` t = -2 * -4 /5 s

`\longrightarrow` t = 8/5 s

`\longrightarrow` t = 1.6 s

Hence the required answer is 1.6s