Question

A ball is kicked from a location < 6, 0, -9> m (on the ground) with initial velocity<-13, 17.0, -4> m/s. The ball's speed is low enough that air resistance is negligible (a) What is the velocity of the ball 0.6 s after being kicked? (Use the Momentum Principle!) 11.2 4 m/S (b) In this situation (constant force), which velocity will give the most accurate value for the location of the ball 0.6 s after it is kicked? the arithmetic average of the initial and final velocities the initial velocity of the ball the final velocity of the ball (c) What is the average velocity of the ball over this time interval (a vector)? -13 19.7 4 m/s (d) Use the average velocity to find the location of the ball 0.6 s after being kicked 1.8 11.82 11.4 Now consider a different time interval: the interval between the initial kick and the moment when the ball reaches its highest point. We want to find how long it takes for the ball to reach this point, and how high the ball goes (e) What is the y component of the ball's velocity at the instant when the ball reaches its highest point (the end of this time interval)? m/s

Answer 1

Solution:

Let us go to the basics of Series and parallel combinations of spring.

Q1

For a single spring

stretch = F / K = 0.4 m ....equation 1

For a parallel combination of springs, effective spring constant is given by

K' = K + K (since both springs are identical)

Thus K' = 2K

So stretch of each spring X = F/K' = F / 2K = 0.4 / 2 = 0.2 m (Answer = Option 1B)

Q2

For a single spring

stretch = F / K = 0.4 m ....equation 1

For a series combination of springs, effective spring constant is given by

1/K' = 1/K + 1/K (since both springs are identical)

Thus K' = K/2

So stretch of each spring X = F/K' = F / (K/2)

= 2F/K = 2* 0.4 = 0.8 m (Answer = Option 2E)

Thanks!!!