Explanation:
Okay soo-
Given-
u = 60 km/hr = 60×1000/3600=50/3 m/s
t = 20 s
s = 250 m
a = ?
v = ?
Solution -
Here, acceleration is uniform.
(a) According to 2nd kinematics equation,
s = ut + ½at^2
250 = 50/3 ×20 + 0.5×a×20×20
250-1000/3=200a
(750-1000)/3=200a
a = -250/(3×200)
a = -5/12
a = 0.4167 m/s^2
The required uniform acceleration of the car is 0.4167 m/s^2.
(b) According to 1st kinematics equation
v = u + at
v = 50/3 + (-5/12)×20
v = 50/3-25/3
v = 25/3
v = 8.33 m/s
The speed of the car as it passes the traffic light is 8.33 m/s.
Good luck!
