Question

answer this quickly....please...you will be marked as brainliest if you answer fast... you can answer any question from the above...I have marked the answer also...but what I need is process...step wise with formulae ....

Answer 1

1. Vo = 0 m/s
Vt = 72 km/h = 72000 m/3600 s = 20 m/s
s = 25 m

Vt² = Vo² + 2as
20² = 0 + 2 . a . 25
400 = 50a
a = 400 : 50
a = 8 m/s² (B)

2. Vo = 270 km/h = 270000 m/3600 s = 75 m/s
Vt = 0 m/s
s = 1000 m

Vt² = Vo² - 2as
0 = 75² - 2 . a . 1000
0 = 5625 - 2000a
2000a = 5625
a = 5625 : 2000
a = 2,8125 m/s²

Vt = Vo - at
0 = 75 - 2,8125 . t
0 = 75 - 2,8125t
2,8125t = 75
t = 75 : 2,8125
t = 26,67 s (A)

3. Vo = 0 m/s
Vt = 72 km/h = 72000 m/3600 s = 20 m/s
t = 1/4 min = 1/4 × 60 s = 15 s

Vt = Vo + at
20 = 0 + a . 15
20 = 15a
15a = 20
a = 20 : 15
a = 4/3 m/s²

Vt² = Vo² + 2as
20² = 0 + 2 . 4/3 . s
400 = 8/3s
s = 400 : 8/3
s = 400 × 3/8
s = 150 m (D)