Average speed= total distance/total time =12km/h
Changing the tilt of the axis from 23 degrees to 45 degrees would dramatically change the seasons. They would be more extreme. Increasing the tilt angle means a larger section of the earth would experience one season for a longer period. There would be longer and colder winters and likewise hotter and longer summers.
If the kinetic energy of each ball is equal to that of the other,
then
(1/2) (mass of ppb) (speed of ppb)² = (1/2) (mass of gb) (speed of gb)²
Multiply each side by 2:
(mass of ppb) (speed of ppb)² = (mass of gb) (speed of gb)²
Divide each side by (mass of gb) and by (speed of ppb)² :
(mass of ppb)/(mass of gb) = (speed of gb)²/(speed of ppb)²
Take square root of each side:
√ (ratio of their masses) = ( 1 / ratio of their speeds)²
By trying to do this perfectly rigorously and elegantly, I'm also
using up a lot of space and guaranteeing that nobody will be
able to follow what I have written. Let's just come in from the
cold, and say it the clear, easy way:
If their kinetic energies are equal, then the product of each
mass and its speed² must be the same number.
If one ball has less mass than the other one, then the speed²
of the lighter one must be greater than the speed² of the heavier
one, in order to keep the products equal.
The pingpong ball is moving faster than the golf ball.
The directions of their motions are irrelevant.
Answer:
a) Her average speed was 0.778 km/min
b) Her average velocity was 0.572 km/min
Explanation:
a) The average speed is given by the traveled distance over time:
average speed = distance / time
average speed = 14.0 km / 18.0 min = 0.778 km/min
b) The average velocity is given by the displacement over time. It is calculated as the variation of the position over time relative to the frame of reference. In this case, the origin of the frame of reference is located at the home of the student. The final position will be the university. Then:
velocity = (final position - initial position)/ time
velocity = 10.3 km / 18.0 min = 0.572 km/min
Acceleration = Change in velocity ÷ Time
29m/s ÷ 4.4s = 6.59 m/s^2
