Explanation:
(a) After the engines stop, the rocket reaches a maximum height at which it will stop and begin to descend in free fall due to gravity.
(b) We must separate the motion into two parts, when the rocket's engines is on and when the rocket's engines is off.
First we must find the rocket speed when the engines stop:
This final speed is the initial speed in the second part of the motion, when engines stop until reach its maximun height. Therefore, in this part the final speed its zero and the value of g its negative, since decelerates the rocket:
So, the maximum height reached by the rocket is:
(c) In the first part we have:
And in the second part:
So, the time it takes to reach the maximum height is:
(d) We already know the time between the liftoff and the maximum height, we must find the rocket's time between the maximum height and the ground, therefore, is a free fall motion:
So, the total time is:
Compared to the emitted radio waves, the radio waves reflected from the vehicle and received by the radar gun have a<u> higher frequency.</u>
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<h3>What is the frequency?</h3>
Frequency is defined as the number of repetitions of a wave occurring waves in 1 second. Its unit is Hz. Frequency is given by the formula as,
A moving car is targeted by radio waves sent from a radar gun by a police officer standing still.
The radio waves reflected off the vehicle and picked up by the radar gun have a greater frequency than the radio waves that were transmitted.
A stationary police officer directs radio waves emitted by a radar gun at a vehicle moving toward the officer.
Compared to the emitted radio waves, the radio waves reflected from the vehicle and received by the radar gun have a<u> higher frequency.</u>
Hence the higher frequency is the correct answer for blanks.
To learn more about the frequency refer;
brainly.com/question/14926605
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#SPJ1
Answer:
292 m
Explanation:
Step one:
given data
initial velocity velocity v= 32 m/s
final velocity u= 0 m/s
acceleration a= 3.5m/s^2
<u>Required</u>
The distance covered upon the application of the brake
Step two:
we know that acceleration
a= v-u/t
t= v-u/a
t= (0-32)/3.5
t=32/3.5
t=9.14seconds
also, to find distance, we use s=d/t,
rearrange as d=s*t
d=32*9.14 s
d=292 m
A. The ball's (vertical) velocity at time is
so that after 4 seconds, the ball's speed is
(The velocity is -10 m/s, so the ball is falling back down at this point.)
B. At maximum height, the ball has zero velocity, so it takes
for the ball to reach this height.
C. The height of the ball at time is
The maximum height is attained by the ball at 3 seconds after it's thrown, so
D. The time it takes for the ball to reach its maximum height is half the time it spends in the air. So the total airtime is .
Put another way: When the ball returns to the height from which it was thrown, its final velocity has the same magnitude as its initial velocity but points in the opposite direction. This is to say, after the total time the ball is in the air, it's final velocity will be -30 m/s. Then the total airtime is
Put yet another way: Solve for . I don't see a need to elaborate...