Question

How much time does it take for a car to accelerate from 3.44 m/s to 20:9 m/s if the average acceleration is 6.00 m/s^2?
3.48 s
0.344 s
4.33 s
2.91 s

A motorcycle at a stoplight takes 4.22 seconds to accelerate to 28.0 m/s after the light turns green. What is it’s average acceleration?
23.78 m/s^2
6.64 m/s^2
3.32 m/s^2
0.15 m/s^2

The change in velocity that occurs at a specific moment in time is known as
Instant acceleration
Average acceleration
Acceleration
Deceleration

Please help with these!

Answer 1

From 1st EQ. of uniform motion
1)20.9-3.44/6=t=2.91 sec


2)28= 0+4.22a
a=6.66m/sec^2

3) Instantaneous acceleration

Answer 2

Answer: a) 2.91s b) 6.64m/s² c) Instant acceleration

Explanation:

a) Acceleration is defined as the change in velocity of an object with respect to time. Mathematically,

Acceleration = change in velocity/time

Change in velocity = final velocity-initial velocity

Acceleration (a) = final velocity (v)/-initial velocity(u)/time(t)

Given final velocity = 20.9m/s

Initial velocity = 3.44m/s

Acceleration = 6m/s²

Time =?

Substituting in the formula we have;

6 = 20.9-3.44/t

6t = 17.46

t = 17.46/6

t = 2.91seconds

b) using the same formula for acceleration in a above;

a = v-u/t

Given v = 28m/s u = 0m/s(since it starts from rest) t = 4.22seconds

a = 28-0/4.22

a = 6.64m/s²

c) The change in velocity that occurs at a specific moment in time is known as Instant acceleration.

We know that acceleration is change in velocity with respect to time. If the acceleration now happens at a specific moment, it is known as instant acceleration i.e acceleration of the body at that instance