Question

8. Can velocity & acceleration point in opposite directions?
9. Define acceleration.​

Answer 1

Answer:

8.If the velocity and acceleration are in the same direction (both have the same sign - both positive or both negative) the object is speeding up. If the velocity and acceleration are in opposite directions (they have opposite signs), the object is slowing down.

9. the rate of change of velocity per unit of time is called as acceleration.

Answer 2

When brakes are applied to a moving car then the car decelerates but it continues to move forward for some time (it doesn't stop immediately). So here the acceleration and velocity are in different directions.

Acceleration is defined as rate of change of velocity

And can be written as:

a=(v-u)/t

where, a denotes acceleration

v denotes final velocity

u denotes initial velocity

t denotes time taken