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1) The acceleration of a train that increases its velocity from 10.0 m/s to 14.0

ID: 251843 • Letter: 1

Question

1) The acceleration of a train that increases its velocity from 10.0 m/s to 14.0 m/s in 3.00 seconds is _____ m/s^2. 2) Preparing for a turn, a bus slows down with an acceleration of -2.0 m/s^2. Calculate how much time it takes the bus to slow down from 12.0 m/s to 5.0 m/s. 3) An 80 kg man starts from rest and after 1.70 seconds is running at a speed of 10.0 m/s. The force needed for this man to get up to this speed in 1.70 seconds is ____ N. 4) If the engines of a jet produce a force of 110,000 N, the acceleration of a 32,000 kg aircraft during takeoff is ____ m/s^2. 5) A 39 N horizontal force pushes on a 3.8 kg mass resting on a horizontal surface. The surface exerts a friction force of 19 N against the motion. The acceleration of the 3.8 kg mass is ____ m/s^2.

Explanation / Answer

Q.1

solution:

acceleration=(v-u)/(time interval)=(14-10)/3=1.33m/s^2

Q.2

solution:

use above formula

t=(5-12)/(-2)=7/2=3.5sec.

Q.3

solution:

force = mass * acceleration

a=(10-0)/1.7=5.88m/s^2              # as u=0, that is initial velocity

force = 80*5.88=470.40N

Q.4

solution:

acceleration=force/mass

a=110000/32000=3.44m/s^2

Q.5

solution:

(applied force)-(frictional force)=(mass)*(acceln)

39-19=3.8*a

=>a=5.26m/s^2