Question

What will be car A’s velocity after 3.0 seconds from start ? 8. If car B is going at 20 m/s and the brakes are applied, how long does it take for it to come to rest ? If car C is going at a speed of 20 m/s and the brakes are applied, what is its speed after 2.0 seconds ?A ball is thrown upward from the ground. Its initial velocity is 15 m/s. If the acceleration due to gravity is 10. m/s2 downward, how long does it take the ball to stop ?

Answer 1

We cannot determine car A's velocity as the necessary information is missing. Car B will take 5.0 seconds to come to rest. Car C will have a speed of 12 m/s after 2.0 seconds.

Step-by-step explanation:

To find the velocity of a car after a certain time, we use the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. For car A, we need the values of u, a, and t to solve the equation. However, the information given in the question does not provide these values for car A, so we cannot determine its velocity after 3.0 seconds.

For car B, which is traveling at 20 m/s and comes to rest, we can use the equation v = u + at and set the final velocity v to 0. Solving for t, we get t = -u/a. Plugging in u = 20 m/s and a = 4.0 m/s², we find that it will take 5.0 seconds for car B to come to rest.

For car C, which is traveling at 20 m/s and wants to find its speed after 2.0 seconds, we can again use the equation v = u + at. Plugging in u = 20 m/s, a = -4.0 m/s² (since the brakes are applied in the opposite direction), and t = 2.0 s, we find that the speed of car C after 2.0 seconds will be 12 m/s.