Answer:
Average velocity v = 21.18 m/s
Average acceleration a = 2 m/s^2
Explanation:
Average speed equals the total distance travelled divided by the total time taken.
Average speed v = ∆x/∆t = (x2-x1)/(t2-t1)
Average acceleration equals the change in velocity divided by change in time.
Average acceleration a = ∆v/∆t = (v2-v1)/(t2-t1)
Where;
v1 and v2 are velocities at time t1 and t2 respectively.
And x1 and x2 are positions at time t1 and t2 respectively.
Given;
t1 = 3.0s
t2 = 20.0s
v1 = 11 m/s
v2 = 45 m/s
x1 = 25 m
x2 = 385 m
Substituting the values;
Average speed v = ∆x/∆t = (x2-x1)/(t2-t1)
v = (385-25)/(20-3)
v = 21.18 m/s
Average acceleration a = ∆v/∆t = (v2-v1)/(t2-t1)
a = (45-11)/(20-3)
a = 2 m/s^2
Because 'acceleration' does NOT mean 'speeding up'.
It means ANY change in motion ... speeding up, slowing down,
or changing DIRECTION.
When traveling a roundabout, or any curved path, the direction
is constantly changing even if the speed is constant, so there is
constant acceleration going on.
For this case, what we must do is to rewrite these measurements in the same unit in order to compare them.
By writing the measurements in meters we have:



Therefore, physically the correct measure is:

Answer:
the length of a student's textbook most likely is:
30 centimeters
See attachment file below.
Hope it helped!
Answer:
friction force
Explanation:
force of friction is opposite to the force applied it resist the motion