Answer:
The frequency of sound heard by the boy is 1181 Hz.
Explanation:
Given that,
Frequency of sound from alarm 
Speed = -8.25 m/s
Negative sign show the boy riding away from the car
Speed of sound = 343
We need to calculate the heard frequency
Using formula of frequency

Where,
= frequency of source
= speed of observer
= speed of source
= speed of sound
Put the value into the formula

here, source is at rest


Hence, The frequency of sound heard by the boy is 1181 Hz.
Answer:
160N
Explanation:
Moments must be conserved - so.


Answer:
Explanation:
There are two types of collision.
(a) Elastic collision: When there is no loss of energy during the collision, then the collision is said to be elastic collision.
In case of elastic collision, the momentum is conserved, the kinetic energy is conserved and all the forces are conservative in nature.
The momentum of the system before collision = the momentum of system after collision
The kinetic energy of the system before collision = the kinetic energy after the collision
(b) Inelastic collision: When there is some loss of energy during the collision, then the collision is said to be inelastic collision.
In case of inelastic collision, the momentum is conserved, the kinetic energy is not conserved, the total mechanical energy is conserved and all the forces or some of the forces are non conservative in nature.
The momentum of the system before collision = the momentum of system after collision
The total mechanical energy of the system before collision = total mechanical of the system after the collision
Gravity slows the upward speed of any rising object by 9.8 m/s every second.
If the ball is tossed upward at 20 m/s, then it's at the top of its arc and its speed has dwindled to zero in (20/9.8) = 2.04 seconds.
During that time, its starting speed is 20 m/s and its ending speed is zero, so its AVERAGE speed all the way up is (1/2) (20 + 0) = 10 m/s .
Sailing upward for 2.04 seconds at an average speed of 10 m/s, the ball rises to (2.04 x 10) = <em>20.4 meters.</em>