Please answer this. Science 7th grade.
1 answer:
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Answer:
Explanation:
Given:
- mass of car,
- distance of skidding after the application of brakes,
- coefficient of kinetic friction,
<u>So, the energy dissipated during the skidding of car:</u>
<em>Frictional force:</em>
where N = normal reaction by ground on the car
<em>Now from the work-energy equivalence:</em>
is the dissipated energy.
Answer: The velocity at different marked time points are given as
t1 = -
t2 = +
t3 = +
t4 = -
t5 = 0
Explanation:
The slope of the tangent of the curve indicates the instantaneous velocity. So if the slope of the tangent is positive, that Is, the tangent makes a positive angle (above the horizontal axis) with the horizontal
axis, then the velocity at this point is positive, and if the slope of the tangent is negative, that is the tangent makes a negative angle with the horizontal axis (below the horizontal axis), then the velocity at this point is negative.
When the tangent of the line is parallel to the horizontal axis, the velocity is 0.
From the position-time graph attached, the sign on the instantaneous velocity for each time marked on the graph is given below
t1 = -
t2 = +
t3 = +
t4 = -
t5 = 0
QED!
