Question

A bus travelling at 90 kmph is forced to slow down to a velocity of 18 kmph due to traffic. If the bus

takes 8 seconds to slow down, calculate its average deceleration.​

Answer 1

Answer:

90 ÷ 18

67

.

then multipl it with 8

.

Answer 2

Step-by-step explanation:

First, let us make some simplifications in notation. Taking the initial time to be zero, as if time is measured with a stopwatch, is a great simplification. Since elapsed time is Δt=tf−t0Δt=tf−t0, taking t0=0t0=0 means thatΔt=tfΔt=tf, the final time on the stopwatch. When initial time is taken to be zero, we use the subscript 0 to denote initial values of position and velocity. That is, x0x0 is the initial position and v0v0 is the initial velocity. We put no subscripts on the final values. That is, t is the final time, x is the final position, and v is the final velocity. This gives a simpler expression for elapsed time, Δt=tΔt=t. It also simplifies the expression for x displacement, which is now Δx=x−x0Δx=x−x0. Also, it simplifies the expression for change in velocity, which is now Δv=v−v0Δv=v−v0. To summarize, using the simplified notation, with the initial time taken to be zero,

Δt=tΔx=x−x0Δv=v−v0,Δt=tΔx=x−x0Δv=v−v0,

where the subscript 0 denotes an initial value and the absence of a subscript denotes a final value in whatever motion is under consideration.