v = final velocity
u = initial velocity
t = time taken
the acceleration of the cyclist is
approximately 3.33 m/s^2
the acceleration of the car is
5.0 m/s^2
Answer:
1. 3 m
2. 27 s
Explanation:
1. "A car traveling at +33 m/s sees a red light and has to stop. If the driver can accelerate at -5.5 m/s², how far does it travel?"
Given:
v₀ = 33 m/s
v = 0 m/s
a = -5.5 m/s²
Unknown: Δx
To determine the equation you need, look for which variable you don't have and aren't solving for. In this case, we aren't given time and aren't solving for time. So look for an equation that doesn't have t in it.
Equation: v² = v₀² + 2aΔx
Substitute and solve:
(0 m/s)² = (33 m/s)² + 2(-5.5 m/s²) Δx
Δx = 3 m
2. "A plane starting from rest at one end of a runway accelerates at 4.8 m/s² for 1800 m. How long did it take to accelerate?"
Given:
v₀ = 0 m/s
a = 4.8 m/s²
Δx = 1800 m
Unknown: t
Equation: Δx = v₀ t + ½ a t²
Substitute and solve:
1800 m = (0 m/s) t + ½ (4.8 m/s²) t²
t ≈ 27 s
Answer:
Option B. 6.25 J/S
Explanation:
Data obtained from the question include:
t (time) = 2secs
F (force) = 50N
d (distance) = 0.25m
P (power) =?
The power can be obtained by using the formula P = workdone/time.
P = workdone / time
P = (50 x 0.25)/ 2
P = 6.25J/s
The answer is C, as there is not increase or decrease in speed during that time frame.
