uniform motion :
1. Same distance is covered (traveled) in equal intervals of time.
2. Distance Time graph shows a straight line. s = v t
3. Speed is constant. If the body is moving in a straight line, velocity is
and acceleration is zero. There is no net force acting on
Displacement always increases and is in one direction.
4. If body is moving in a circle, the speed v is constant and acceleration
= v²/R .
Acceleration points towards the center of
circle. There is a centripetal force
acting on the body.
Displacement increases and
decreases in magnitude and changes in
direction. Centripetal force is constant.
Bodies moving in uniform speed
1. Earth rotates around itself with a people on the surface moving at a uniform
tangential speed (almost)
So all of us are moving with a uniform speed
(tangential) in circles, with
respect to a stationary observer outside earth. We
have not taken into
account the revolution of earth around Sun here.
Our speed = radius
of earth * angular velocity
= 6400 km * 2 π / 24 hours = 1675.5 kmph
2. Trains and air planes move with uniform speed in between halts.
stations or airports, they accelerate or decelerate. An
covers usually around 60 km in 3/4 hour non-stop
between two big stations.
= 60 / (3/4) = 80 kmph
5. Speed of Birds flying in air = distance traveled / time = 15
= 54 kmph
7. Hard disk inside the computer. It rotates at uniform speed.
speed = 4,000 rpm - 10,000 rpm
9. Light wave moves at uniform speed of c = 3 * 10^8
10. A fan (ceiling) rotates at a uniform speed, same with the blade in a
kitchen - mixie or mixer.
Tip of Fan wing : radius = 0.80 meter,
smallest speed = 5 rotations per sec
Angular speed = 5 * 2 p radians/sec = 10
Uniform Linear speed of the tip (far end
of a wing)
= 0.80 * 10 p m/sec = 25.13m/s = 90.5 kmph
11. Blood inside our body moves (circulates) at uniform speed
Pulse rate = 72 /min
distance from heart to a hand/leg = 2.5 m
Speed of blood flow = around 2.5m
* 72 / min
= 180 m / min = 180 * 60/1000 = 10.8 kmph