Question

If a body moves with 30 m/s for 5 mins and 40 m/s for next 2 min. Calculate average speed of the body​

Answer 1

ANSWER:

• The average speed of the body = 32.86 m/s.

GIVEN:

• A body moves with 30 m/s for 5 mins and 40 m/s for next 2 min.

TO FIND:

• The average speed of the body.

CONVERSIONS :

• 1 min = 60 seconds.

• 5 min = 5 × 60 = 300 s.

• 2 mins = 2 × 60 = 120 s.

EXPLANATION:

$\boxed{ \bold{ \large{ \gray{Avg \ speed = \dfrac{Total\ distance}{ Total \ time}}}}}$

$\boxed{ \bold{ \large{ \gray{Distance = speed \times time}}}}$

$\sf Total \ distance = d_1 + d_2$

$\sf d_1 = s_1 \times t_1$

$\sf s_1 = 30 \ ms^{-1}$

$\sf t_1 = 300\ s$

$\sf d_1 = 30 \times 300$

$\sf d_1 = 9000 \ m$

$\sf d_2 = s_2 \times t_2$

$\sf s_2 = 40 \ ms^{-1}$

$\sf t_2=120\ s$

$\sf d_2 = 40 \times 120$

$\sf d_2 = 4800$

$\sf Total \ distance =13800$

$\sf Total \ time = t_1 + t_2$

$\sf Total \ time = 300 + 120$

$\sf Total \ time = 420$

$\sf Avg \ speed = \dfrac{13800}{ 420}$

$\sf Avg \ speed = 32.86 \ m {s}^{ - 1}$

HENCE THE AVERAGE SPEED = 32.86 m/s.

Answer 2

Step-by-step explanation:

A body moves with 30 m/s for 5 mins and 40 m/s for next 2 min.

Convert min into sec. To do this multiply the given value by 60.

t1 = 5 × 60 = 300 sec and t2 = 2 × 60 = 120 sec

Distance = Speed × Time

d1 = 30 × 300

d1 = 9000 m

d2 = 40 × 120

d2 = 4800 m

Average speed = Total distance/Total time

Total distance covered = d1 + d2

= 9000 + 4800

= 13800 m

Total time taken = t1 + t2

= 300 + 120

= 420 sec

Therefore,

Average speed = 13800/420 = 32.86 m/s