Question

The velocity of a car changes from 18 km h^-1 in 30 s. Calculate (i) change in velocity in ms^-1 (ii) acceleration in km h^-2 and ms^-2​

Answer 1

Answer:

Correct Question:-

The velocity of a car changes from $18 \: km \: h {}^{ - 1}$to $72 \: km \: h {}^{ - 1}$in 30 s. Calculate (i) Change in velocity in $ms {}^{ - 1}$ (ii) Acceleration in $km \: h {}^{ - 2}$and $ms {}^{ - 2}$

Solution:-

Change in velocity

= (72 – 18) $km \: h {}^{ - 2}$ $</p><p>= 54 \: km \: h {}^{ - 1}$

Thus, change in velocity in $ms {}^{ - 1} =54 \times \frac{5}{8} \: ms {}^{ - 1} \\ \\ = 15 \: ms {}^{ - 1}$

Now, we know that acceleration = Change in velocity/Time

So, acceleration in km h$^{–2}$

= Change in velocity/Time

$= \frac{54 \: km \: h {}^{ - 1} }{ \frac{30}{3600}h } \\ \\ = 54 \times 120 \: km \: h {}^{ - 2} \\ \\ = 6480 \: km \: h {}^{ - 2}$

Acceleration in ms$^{–2}$

= Change in velocity/Time

$= \frac{15 \: ms {}^{ - 1} }{30 \: s} \\ \\ = 0.50 \: ms {}^{ - 2}$

Answer 2

Answer:

0.50ms-2will be the correct answer hope it helps you