Question

A train accelerates uniformly at 6.5 m/s² for 20s. If the train starts from rest, calculate the distance travelled in 15 seconds?
Solution

Answer 1

Answer:

325 meter per second is the distance traveled

Answer 2

Answer:

motion with acceleration 2 m/s2 for 10 seconds.

Distance travelled S1 = u×t+(1/2)×a×t2 , where u is initial speed (u=0, starts from rest), a acceleration and t is time of travel

S1 = (1/2)×2×10×10 = 100 m ...................(1)

speed v after 10 seconds :- v = u+a×t = 0 + 2×10 = 20 m/s

(b) motion with constant velocity

Distance travelled S2 = velocity×time = 20×40 = 800 m .................(2)

(c) break applied

stops after 20 seconds ; hence retardation will be obtained from "v = u - a×t " with v =0

retardataion a = u/t = 20/20 = 1 m/s2

distance travelled S3 = u×t - (1/2)×a×t2 = 20×20 -(1/2)×1×20×20 = 200 m. ...............(3)

(1) maximum velocity reached = 20 m/s = 20 × (18/5) = 72 km/hr

(2) retardation in last 20 s = 1 m/s2

(3) Total distance travelled = S1+S2+S3 = 100+800+200 = 1100 m

(4) average velocity = distance / time = 1100/70 = 110/7 m/s = 110/7 × (18/5) = 56.6 km/hr

Answered by Thiyagarajan K | 23rd May, 2018, 01:59: PM

Related Videos

Acceleration - Part 1

Define acceleration and retardation in context with uniform...

Distance-Time Graph - Part 1

Interpret and calculate the slope of distance. Time graphs ...

Equations of Motion

Derive and apply the three equations of motion using veloci...

Velocity

Interpret and calculate the slope of velocity. Time graphs ...

Newton's First Law of Motion

Explain Newton's first law of motion with Galileo's experim..

◢