A racing car traveling with constant acceleration increases its speed from 10 m/s to 30 m/s over a distance of 60 m? How long does this take?
A)2.0 s
B)3.0 s
C)5.0 s
D)6.0 s
E)The time cannot be calculated since the speed is not constant

Question

Quizplus · Accepted Answer

We can use the formula: 
v^2 = u^2 + 2as 
where: 
v = final velocity = 30 m/s 
u = initial velocity = 10 m/s 
a = acceleration 
s = distance = 60 m

Rearranging the formula: 
a = (v^2 - u^2)/2s

Substituting the values: 
a = (30^2 - 10^2)/(2*60) = 20 m/s^2

We can use another formula to find the time taken: 
t = (v - u)/a

Substituting the values: 
t = (30 - 10)/20 = 1 s

Therefore, the time taken is 1 second. However, it is important to note that the acceleration was constant during the entire duration, hence we were able to use the above formulas.

A Racing Car Traveling with Constant Acceleration Increases Its Speed