Answer:
S = Vo t + 1/2 a t^2 distance traveled
t = (V2 - V1) / a = (0 - 21) / -3.5 = 6 sec time to stop
S = 21 * 6 - 3.5 * 6^2 / 2 = 63 m distance traveled
Acceleration = change in velocity/time
= 40/5
=8m/s^2
A)
It is a launch oblique, therefore the initial velocity in the vertical direction is zero. Space Hourly Equation in vertical, we have:
Through Definition of Velocity, comes:

B)
Using the Velocity Hourly Equation in vertical direction, we have:
The angle of impact is given by:

If you notice any mistake in my english, please let me know, because i am not native.
Option C
The fact that voltage can be created by exerting force on a crystal is used in Knock sensor
<u>Explanation:</u>
Any knock to an engine exhibits as a little shake that is distinguished by the knock sensor. This sensor acts by altering the fluctuation to an electrical sign, which is later transferred to the processor mastering the ignition system.
There the variation in quake to the voltage sign modifies the timing improvements on the kindling. The knock sensor is placed on the engine base, cylinder cap or consumption manifold. This is because its purpose is to sense fluctuations affected by engine knock or explosion.
Answer: Place his feet parallel to the baseline prior to tossing the ball