1. Express 90 km/hr in meters per second.

A. 10 m/sec

B. 25 m/sec

C. 30 m/sec

D. 15 m/sec

To convert km/hr into m/sec multiply with $\frac{5}{18}$ 90 $\times $ $\frac{5}{18}$ = 25 m/sec

2. Express 22 meters per second in km/hr.

A. 10 m/sec

B. 25 m/sec

C. 30 m/sec

D. 15 m/sec

To convert m/sec into km/hr multiply with $\frac{18}{5}$ 22 $\times $ $\frac{18}{5}$ = $\frac{396}{5}$ = 79.2 km/hr

3. A man travelled 12 minutes at the speed of 3.5 km/hr. Express his travelled distance in meters.

A. 10 m/sec

B. 25 m/sec

C. 30 m/sec

D. 15 m/sec

Time = 12 minutes = $\frac{12}{60}$ hours Speed = 3.5 km/hr Distance = speed $\times $ time 3.5 $\times $ $\frac{12}{60}$ = $\frac{7}{10}$ km Distance in meters = $\frac{7}{10}$ $\times $ 1000 = 700 meters

4. 180 meter long train crosses a man standing on the platform in 6 seconds. What is the speed of the train ?

A. 10 m/sec

B. 25 m/sec

C. 30 m/sec

D. 15 m/sec

Speed = $\frac{Distance}{Time}$ = $\frac{180}{6}$ = 30 meters 30 $\times $ $\frac{18}{5}$ = 108 km/hr

5. How many minutes does Ashok take to cover a distance of 400 meters if he runs at a speed of 20 km/hr ?

A. 10 m/sec

B. 25 m/sec

C. 30 m/sec

D. 15 m/sec

Ashokâs speed = 20 km/hr = $(20\times \frac{5}{18})$m/sec $=$ $(\frac{50}{9})$ m/sec Time taken to cover 400 meters = $(400\times \frac{9}{50})$sec = 72 sec = 1$\frac{1}{5}$ minutes