a)The average acceleration of the car is
b) The distance travelled is 560 m
<u>Explanation:
</u>
a) Acceleration is defined as the rate of change in velocity per unit time. So it can be obtained by measuring the ratio of speed to time.
Since here the initial speed was zero and final speed is given as 28 m/s, then time is given as 20 s. So,
b) As the speed is given as 28 m/s, then
So the distance travelled is 560 m and average acceleration is .
We only need to look at Newton's 2nd law of motion:
Net force = (mass) x (acceleration)
If the net force on an object is zero, then either its mass or its acceleration must be zero. If it's called an "object", then its mass isn't zero, so its acceleration is zero.
The options are;
a. V2 equals 2V1.
b. V2 equals (V1)/2.
c. V2 equals V1.
d. V2 equals (V1)/4.
e. V2 equals 4V1.
Answer:
Option A: V2 equals 2V1
Explanation:
Since the flow is steady, then we can say;
mass flow rate at input = mass flow rate at output.
Formula for mass flow rate is;
m' = ρVA
Thus;
At input;
m'1 = ρ1•V1•A1
At output;
m'2 = ρ2•V2•A2
So, m'1 = m'2
Now, we are told that the density of the fluid decreases to half its initial value.
Thus; ρ2 = (ρ1)/2
Since m'1 = m'2, then;
ρ1•V1•A1 = (ρ1)/2•V2•A2
Now, the pipe is uniform and thus the cross section doesn't change. Thus;
A1 = A2
We now have;
ρ1•V1•A1 = (ρ1)/2•V2•A1
A1 and ρ1 will cancel out to give;
V1 = (V2)/2
Thus, V2 = 2V1