Answer:
When acceleration is zero (that is, a = dv/dt = 0), rate of change of velocity is zero. That is, acceleration is zero when the velocity of the object is constant. so probably D
Explanation:
D
The answers for this question are:
a. You push a box until it moves. = unbalanced
b. You push a box but it doesn't move. = balanced
c. <span>You stop pushing a box and it slows down. = unbalanced
As a general explanation for all the items, forces are considered balanced when they cancel each other out. This means that no net force is produced. A and C are unbalanced because one force was able to overcome the force exerted by the object.</span>
Acceleration can be any change in speed, increasing or decreasing.
You haven't said whether the ball is speeding up or slowing down.
If its acceleration is positive ... speed is increasing ... then in 2.5 seconds,
it GAINS (0.5 m/s² x 2.5 sec) = 2.5 m/s of speed. Added to its initial
speed of 2.0 m/s, it ends up moving at 4.5 m/s.
If its acceleration is negative ... speed is decreasing ... then in 2.5 seconds,
it LOSES (0.5 m/s² x 2.5 sec) = 2.5 m/s of speed. Added to its initial
speed of 2.0 m/s, it ends up moving at -0.5 m/s. That means that it ends up
moving in the opposite direction compared to its direction at the beginning of
the change.
Answer:
The car will travel 30 miles during the 30-minutes period of acceleration.
Explanation:
Given data :
Initial velocity = v₁ = 50 miles/hour
Final velocity = v₂ = 70 miles/hour
Time = t = 30 min = 0.5 hour
Using the definition of acceleration, we find the acceleration (a)
a = (v₂ - v₁) ÷ t
a = (70 - 50) ÷ 0.5
a = 20 ÷ 0.5
a = 40 miles/hour²
Using 3rd equation of motion, we find the distance travel (s)
2as = v₂² - v₁²
2(40)s = 70² - 50²
80 × s = 4900 - 2500
s = 2400 ÷ 80
s = 30 miles