A body of mass $\mathrm{m}=3.513 \mathrm{~kg}$ is moving along the x-axis with a speed of $5.00 \mathrm{~ms}^{-1}$. The magnitude of its momentum is recorded as

(A) $17.6 \mathrm{~kg} \mathrm{~ms}^{-1}$

(B) $17.565 \mathrm{~kg} \mathrm{~ms}^{-1}$

(C) $17.56 \mathrm{~kg} \mathrm{~ms}^{-1}$

(D) $17.57 \mathrm{~kg} \mathrm{~ms}^{-1}$

JEE Main · 2008 · 27 Apr 2008 · Offline · Units & Measurement

A body of mass

m = 3.513 kg

is moving along the x-axis with a speed of

5.00 ms^{- 1}

. The magnitude of its momentum is recorded as

Answer: (A)

Momentum is mass times velocity,

p = 3.513 \times 5.00 = 17.565 kg m s^{- 1}

as a bare product. The reported value, though, can be no more precise than the least precise measurement feeding it, and the speed

5.00 m s^{- 1}

carries only three significant figures. Rounding the product to three significant figures gives

p = 17.6 kg m s^{- 1}

JEE Main · 2008 · 27 Apr 2008 · Offline · Single correct option