Question

in an experiment to measure the speed of moving ball it is observed that the ball covers a distance of 5 metre and 20 CM in 4 seconds before it comes to stop .calculate the speed of the ball in metre per second​

Answer 1

${\bold{\underline{\underline{Answer:}}}}$

${\bold{\therefore Initial\:speed=2.6\:m/s}}$

${\bold{\underline{\underline{Step-by-step\:explanation:}}}}$

• In the given question information given about the speed of moving ball it is observed that the ball covers a distance of 5 metre and 20 CM in 4 seconds before it comes to stop.

• We have to find Initial speed of ball.

$\underline \bold{Given : } \\ \implies Distance(s) = 5.2 \: m \\ \\ \implies Time(t) = 4 \: sec \\ \\ \implies Final \: speed(v) = 0 \: m/s \\ \\ \underline \bold{To \: Find : } \\ \implies Initial \: speed(u) = ?$

• Accirding to given question :

$\bold{Using \:first \: equation \:of\:motion: } \\ \implies v = u + at \\ \\ \implies 0 = u + a \times 4\\ \\ \implies - u= 4a \\ \\ \implies a = \frac{ - u}{4} \\ \\ \bold{Using \: third \: equation \: of \:motion: } \\ \implies s = ut + \frac{1}{2} {at}^{2} \\ \\ \bold{Putting \: value \: of \: a} \\ \implies 5.2 = u \times 4 + \frac{1}{2} \times \frac{ - u}{4} \times {4}^{2} \\ \\\implies5.2=u\times 4+\frac{1}{\cancel2}\times\frac{-u}{\cancel4}\times\cancel4\times\cancel4\\ \\ \implies 5.2 = 4u + ( - 2u) \\ \\ \implies 5.2 = 4u - 2u \\ \\ \implies u = \frac{5.2}{2} \\ \\ \bold{\implies u = 2.6 \: m/s}$

Answer 2

Answer:

• Initial speed =2.6 m/s

Explanation:

$\bold{Using \:first \: equation \:of\:motion: } \\ \implies v = u + at \\ \\ \implies 0 = u + a \times 4\\ \\ \implies - u= 4a \\ \\ \implies a = \frac{ - u}{4} \\ \\ \bold{Using \: third \: equation \: of \:motion: } \\ \implies s = ut + \frac{1}{2} {at}^{2} \\ \\ \bold{Putting \: value \: of \: a} \\ \implies 5.2 = u \times 4 + \frac{1}{2} \times \frac{ - u}{4} \times {4}^{2} \\ \\5.2=u\times 4+\frac{1}{2}\times\frac{-u}{4}\times4\times\4\\ \\ \implies 5.2 = 4u + ( - 2u) \\ \\ \implies 5.2 = 4u - 2u \\ \\ \implies u = \frac{5.2}{2} \\ \\ \bold{\implies u = 2.6 \: m/s}$