Question

5 + 25 = 30 ms
Práctice Problems 3
1. A dog initially running at a speed of 2 m/s, accelerates at a constant rate of 1.5 m/s2 for 5 s.
Calculate (i) the distance covered by the dog from its initial position, (ii) the final velocity of
the dog
[(i) 28.75 m (ii) 9.5 m/s]
2. A racing car initially at rest, accelerates at a uniform rate of 5.5 m/s2 for 10 s. Calculate
(1) the distance covered by the racing car from start, and (ii) the final velocity in km/h.
[(i) 275 m (ii) 198 km/h)​

Answer 1

Explanation:

1. S = ut + ½at²

= 2 x 5 + ½ x 1.5 x 5²

= 10 +( 15 x 25)/20

= 10 + 75/4

= 115/4

= 28.75m

ii. v - u = at

v = u +at

= 2 + 1.5x 5

= 19/2

= 9.5 m/s

2. I. s = ut + ½ at²

= 0x 10 + ½ x 5.5 x 100

= 55 x 5

= 275 m

ii. V-U = at

v = u +at

= 0 + 5.5 x 10

= 55 m/s

= 55 x 18/5 km /hr

= 198 km/h