Answer:
Explanation:
1) Data:
a) m =750 kg
b) V₀ = 0 (at rest at the red light)
c) a = 7.8 m/s²
d) t = 7.0 s
e) Vf (at t = 7 s) = ?
2) Physical principles and formulae
Uniformly accelerated motion is ruled by the equations:
i. Vf= V₀ + at
ii. d = V₀ t + at² / 2
iii. Vf² = V₀² + 2ad
Where:
- V₀ = initial speed
- Vf = final speed
- a = acceleration
- d = distance run
3) Solution
You just need to use the first equation:
- Vf= V₀ + at = 0 + 7.8 m/s² × 7 s = 74.6 m/s
- Round to two significant figures: 75 m/s
