Question

1

An object is moving in a circular path of radius 3.5m. If
completes one full cycle, what will be the displacement and what is
the distance travelled?
2
An object changes its velocity from 30 ms' to 40 ms' in a time
interval of 2s. What is its acceleration?
3. An object at rest starts moving. It covers a distance of 2m
in one second. It covers a further distance of 5 m in two
seconds in the same direction. What is its average velocity and
acceleration?
IV. Answer the following
1. If a body is moving with uniform velocity in a given direction its
acceleration will be zero. Why?
2. Distinguish between speed and velocity.
3. Distinguish between distance travelled and displacement.
4. What are uniform and non-uniform speed?
5. While mentioning acceleration the time is mentioned two times.
Why?
tended activity​

Answer 1

Answer:

Explanation:

(1): As it is a circle, it reaches to the same point where it started, so displacement(distance b/w final and initial point) is 0.

distance = perimeter of circle  

               = 2πr = 2π(3.5m)

               = 22 m

(2): Acceleration = (change in velocity/time taken)

               = (40 - 30)/2   m/s^2

               = 10/2     m/s^2

               = 5   m/s^2

(3): In 1st sec = 2

       2nd & 3rd sec = 5 m

Total time = 3 sec   ;  

distance = 5 + 2 m = 7 m

        Hence, speed = (7/3)  m/s

Since direction is same, velocity = speed = (7/3) m/s

As it was at rest, velocity was 0.

Acceleration,thus, = (7/3 - 0)/3 = 7/9  m/s^2

 IV ; ; ; ; ; ;

1. As velocity is uniform, it doesnt changes in same time period.

In t sec to t + 1 sec, speed = x

So, in t + 2 to t + 3 , speed =  x

  This is what we call uniform speed.

Therefore, acceleration will be 0.

2. Speed is scalar, it has only magnitude(numeric value)

  whereas velocity is vector, it direction and magnitude both.

3. Distance is scalar, t has only magnitude(numeric value)

  whereas displacement is vector, it direction and magnitude both.

4. As said above, if it doesn't change in same time period , it is uniform , otherwise non-uniform.

5. Acceleration says about the change in speed(which has time), with respect to time. Mathematically;

  Acce. = (m/s  -  m/s)/s  = m/s^2