2. Observe: What is the initial value of vy? 57.45 m/s 3. Calculate: The vertical velocity of a projectile is found with the equation: Vy - Vylinitial) – gt.
A. What will be the value of Vy when the ball is at the top of its trajectory?!
B. Using the equation above, solve for t when Vy = 0.0 m/s, Vy(initial) = 57.45 m/s, and
g = 9.81 m/s?
C. Now use the same method to determine how long it will take the ball to fall from its
maximum height to the ground:
D. Based on your answers to B and C, how long will the ball spend in the air?

the small 0.38-kg slider is known to move from position a to position b along the vertical-plane slot. determine (a) the work done on the body by its weight and (b) the work done on the body by the spring. the distance r = 0.70 m, the spring modulus k = 154 n/m, and the unstretched length of the spring is 0.53 m

explanation:

-reverse card

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me