Question

1-A train travels 100 km to reach town A in one hour and 15 min. The train stops at station A for 45 minutes. Then it travels 150 km to station B in 2 hours. What is the average velocity of the train?
Average velocity= displacement/time

2-A car accelerates uniformly at the rate of 1.2 meters per second squared for a distance of 75 meters. If the truck started with a initial velocity of 6 meters per second, what is its velocity at the end of the 75 meters?
vf^2=vi^2 + 2as

Answer 1

Answer 1) : 62.5 km/hour is the average velocity of the train.

2) The final velocity of the car at the end of 75 m is 14.69 m/s

Explanation:

1) Displacement of the train = 100 km + 150 km = 250 km

Total time train took =1 hour 15 min+ 45 min + 2 hours = 240 min = 4 hours

Average velocity=$\frac{Displacement}{time}=\frac{250 km}{4 hour}=62.5 km/h$

62.5 km/hour is the average velocity of the train.

2) The acceleration of the car, a= 1.2 $m/s^2$

Distance covered by the car,s = 75 m

Initial velocity of the car ,$v_i$ = 6 m/s

Final velocity of thre car ,$v_f$=?

Using third equation of motion:

$v_{f}^2=v_{i}^2+2as=(6 m/s)^2+2\times 1.2 m/s\times 75 m=216 m^2/s^2$

$v_{f}=14.69 m/s$

The final velocity of the car at the end of 75 m is 14.69 m/s