78. The initial velocity of a projectile has a horizontal
component equal to 5 m/s and a vertical component
equal to 6 m/s.
At the highest point of the projectile's flight, what is (a) the horizontal component of its
velocity and
(b) the vertical component of its velocity?
Explain.

Consider again the cannonball launched by a cannon from the top of a very high cliff. Suppose that the cannonball is launched horizontally with no upward angle whatsoever and with an initial speed of 20 m/s. If there were no gravity, the cannonball would continue in motion at 20 m/s in the horizontal direction. Yet in actuality, gravity causes the cannonball to accelerate downwards at a rate of 9.8 m/s/s. This means that the vertical velocity is changing by 9.8 m/s every second. If a vector diagram (showing the velocity of the cannonball at 1-second intervals of time) is used to represent how the x- and y-components of the velocity of the cannonball is changing with time, then x- and y- velocity vectors could be drawn and their magnitudes labeled. The lengths of the vector arrows are representative of the magnitudes of that quantity. Such a diagram is shown below.

Explanation: i hoped that helped!

d. platinum would have the greatest temperature increase because it has the lowest specific heat.