I believe the correct answer is C
Answer:
Explanation:
Let Vc be the velocity of the car and Vm the velocity of the motorcycle. If we convert their given values, we get:
Vc = 87 km/h * 1000m / 1km * 1h / 3600s = 24.17m/s
Vm = 95 km/h * 1000m / 1km * 1h / 3600s = 26.38m/s
Since their positions are equal after 17s we can stablish that:
Where d is the initial separation distance of 54m. Solving for a, we get:
Repacing the values:
Answer:
-120000 W
Explanation:
Power = change in energy / time
P = ΔE / t
P = (½ mv₂² − ½ mv₁²) / t
P = m (v₂² − v₁²) / (2t)
Given m = 1.5 t = 1500 kg, v₂ = 10 m/s, v₁ = 30 m/s, and t = 5 s:
P = (1500 kg) ((10 m/s)² − (30 m/s)²) / (2 × 5 s)
P = -120000 W
Answer:
C) they all have the same angular speed
D) they all have the same angular acceleration
Explanation:
Wrong --> they all have the same tangential speed. The points close to the axis will have less speed than the points away from the axis.
Wrong --> they all have the same tangential acceleration. Similarly, the points close to the axis will have smaller acceleration than the points away from the axis.
Correct --> they all have the same angular speed. Angular speed is the same for all the particles in the rotating object.
Correct --> they all have the same angular acceleration. Angular acceleration is the same for all the particles in the rotating object.
This all comes from the following relations:
v = ωR
a = αR
where ω is the angular velocity and α is the angular acceleration.
As can be seen from above, tangential velocity and acceleration depends on the distance from the axis, whereas the angular velocity and acceleration is the same for all the points on the rotating body.