Class 9 Physics- Conceptual Motion Problems and Solution

Question 1. A object goes from point X to Y and then come back from Y to X. What is the displacement and average velocity?

Displacement is zero as it come back to it initial point.
Now Average velocity is given Displacement/time. Since displacement is zero, Average velocity is also zero

Question 2. Write down the difference between Scalars and Vectors?

S.No	Scalars	Vectors
1	It has magnitude only	It has magnitude and direction both
2	Example are speed,time,mass,charge	Example are velocity,displacement,acceleration,force

Question 3. Four Cyclist A,B,C ,D starts at the same point and at the same time and move in a straight line to reach destination .They all move with uniform velocities. They reach the destination in the following order
$C\to A\to B\to D$
Answer the following questions
a. If the displacement-time graph is plotted for each cyclist, which will be having highest slope
b. Arrange the cyclist in decreasing order of velocity

Since C is fastest cyclist, it velocity is highest and Slope of displacement time graph will be highest for him Velocity of cyclist in decreasing order 
$C>A>B>D$

Question 4. What do you infer if ? 

	Distance –time graph is straight line
2	Velocity –time graph is curved
3	Displacement –time is zig zag

	Distance – time graph is straight line	Speed is constant
2	Velocity – time graph is curved	Acceleration is not uniform
3	Displacement – time is zig zag	Non uniform velocity

Question 5. What is the difference between Uniform Accelerated and Non Uniform accelerated motion?

No	Uniformly accelerated	Non uniformly accelerated
1	A body is said to be in uniform acceleration if it travels in a straight line and its velocity increases or decreases by equal amounts in equal intervals of time.	A body is said to be in non uniform acceleration if the rate of change of its velocity is not constant in equal intervals of time
2	Motion under acceleration under gravity is perfect example for uniform accelerated motion	A car moving in a straight line. Some time putting more pressure on the accelerator pedal is a perfect example of non uniform accelerated motion.
3	Following equations could be use here $v^2=u^2+2aS$  $v=u+at$  $s=ut+\frac{1}{2}a{t}^2$	No equation available