A body moving with a velocity of 50m/s is brought to rest in 30s by a constant retarding force. Calculate the distance covered by the body

John Perolski
August 22, 2023

Physics Jamb, Waec, Neco Past Questions & Answers on Speed, Velocity and Acceleration

QUESTION 57. A body moving with a velocity of 50m/s is brought to rest in 30s by a constant retarding force. Calculate the distance covered by the body. 

NECO 2008 Ans. 750m 

SOLUTIONS 

  • initial velocity u ,= 50m/s
  • Final velocity v = 0m/s
  • Time taken t = 30s
  • Distance covered s =?

Acceleration = deceleration = change in velocity/time 

a = ∆v/t

a = 0 - 50/30

a = -50/30 

a = -5/3 = -1.67m/s²

Using V² = U² + 2as

0² = 50² + 2(1.67)s

0 = 2500 + 3.34s

-2500 = 3.34 X s

S = -2500/3.34

S = -(-)748.50 ~ = 749m

OR

Using s = ut + ½at²

S = 50 (30) + ½(-1.7)(30)²

S = 1500 - ½(1.7)(900)

S = 1500 - 1503/2

S = 1500 - 751.5

S = 748.5m ~ = 749.0m ANSWER