Answer:
a. 4.28 m/s
b. 1.65 m/s²
Explanation:
a.
Speed: This can be defined as the ratio of distance to time. The S.I unit of speed is m/s.
From newton's equation of motion,
S = (v+u)t/2 ............................... Equation 1
Where S = distance, u = initial speed, v = final speed, t = time.
Given: S = 72 m, v = 16.0 m/s, t = 7.10 s.
Substitute into equation 1
72 = (16+u)7.10/2
making u the subject of the equation,
7.1(16+u) = 72×2
113.6+7.1u = 144
7.1u = 144-113.6
7.1u = 30.4
u = 30.4/7.1
u = 4.28 m/s
Thus the speed at the first point = 4.28 m/s
b.
Acceleration: This can be defined as the rate of change of velocity. The S.I unit of acceleration is m/s²
a = (v-u)/t............................ Equation 2
Where a = acceleration.
Given: v = 16.0 m/s, u = 4.28 m/s, t = 7.10 s
Substitute into equation 2,
a = (16-4.28)/7.1
a = 11.72/7.10
a = 1.65 m/s²
Thus the acceleration = 1.65 m/s²
