Answer:
4a. –2.5 m/s²
4b. 375 m
5. 7.5 s
Step-by-step explanation:
4. The following data were obtained from the question:
Initial velocity (u) = 50 m/s
Final velocity (v) = 25 m/s
Time (t) = 10 s
Acceleration (a) =?
Displacement (s) =?
4a. Determination of the acceleration of the car.
Initial velocity (u) = 50 m/s
Final velocity (v) = 25 m/s
Time (t) = 10 s
Acceleration (a) =?
a = (v – u) /t
a = (25 – 50)/10
a = –2.5 m/s²
The negative sign indicate that the car is decelerating.
4b. Determination of the displacement of the car.
Initial velocity (u) = 50 m/s
Final velocity (v) = 25 m/s
Time (t) = 10 s
Displacement (s) =?
s = (v + u)t / 2
s = (25 + 50) × 10 / 2
s = (75 × 10) / 2
s = 750 / 2
s = 375 m
Thus, the displacement of the car is 375 m
5. The following data were obtained from the question:
Initial velocity (u) = 30 m/s
Final velocity (v) = 0 m/s
Acceleration (a) = – 4m/s²
Time (t) =?
The time taken for the car to stop can be obtained as follow:
v = u + at
0 = 30 + (–4 × t)
O = 30 – 4t
Collect like terms
0 – 30 = –4t
–30 = –4t
Divide both side by –4
t = –30 / –4
t = 7.5 s
Thus, it will take 7.5 s for the car to completely stop.