Consider a block of mass `10 kg`. which rests on as smooth surface and is subjected to a horizontal force of `6N`. If observer `A` is in a fixed frame `x`.

Options

A. The final speed of the block in `4 s` is `7.4 ms^(-1)` , if it has initial speed of `5 ms^(-1)` measured from fixed frame.
B. Same speed will be observed by an observer `B`, attached to the `x' ` axis that moves at a constant velocity of `2 ms^(-1)` relative to `A`
C. Principle of impulse and momentum is valid for observers in any inertial reference frame
D. Momentum of a body is reference frame dependent.

Answer

A, C, D

Explanation

Impulse `=` change in mometum
`implies 6xx4=10(v-5)impliesv=7.4ms^(-1)`
w.r.t observer `B`, speed will be `v-2=7.4-2=5.4ms^(-1)`