f' = frequency observed by the police car after sound reflected from the vehicle and comes back to police car = 1250 Hz
f = frequency emitted by the police car = 1200 Hz
V = speed of sound = 340 m/s
v = speed of vehicle = ?
frequency observed by the police car is given as
f' = f (V + v)/(V - v)
inserting the values in the above equation
1250 = 1200 (340 + v)/(340 - v)
v = 6.9 m/s
Answer:
The vertical distance is ![d = \frac{2}{k} *[mg + f]](https://tex.z-dn.net/?f=d%20%3D%20%5Cfrac%7B2%7D%7Bk%7D%20%2A%5Bmg%20%2B%20f%5D)
Explanation:
From the question we are told that
The mass of the cylinder is m
The kinetic frictional force is f
Generally from the work energy theorem

Here E the the energy of the spring which is increasing and this is mathematically represented as

Here k is the spring constant
P is the potential energy of the cylinder which is mathematically represented as

And
is the workdone by friction which is mathematically represented as

So

=> ![\frac{1}{2} * k * d^2 = d[mg + f ]](https://tex.z-dn.net/?f=%20%5Cfrac%7B1%7D%7B2%7D%20%2A%20k%20%20%2A%20%20d%5E2%20%3D%20%20d%5Bmg%20%2B%20%20f%20%20%20%20%5D)
=> ![\frac{1}{2} * k * d = [mg + f ]](https://tex.z-dn.net/?f=%20%5Cfrac%7B1%7D%7B2%7D%20%2A%20k%20%20%2A%20%20d%20%3D%20%20%5Bmg%20%2B%20%20f%20%20%20%20%5D)
=> ![d = \frac{2}{k} *[mg + f]](https://tex.z-dn.net/?f=d%20%3D%20%5Cfrac%7B2%7D%7Bk%7D%20%2A%5Bmg%20%2B%20f%5D)
Answer:
The minimum speed when she leave the ground is 6.10 m/s.
Explanation:
Given that,
Horizontal velocity = 1.4 m/s
Height = 1.8 m
We need to calculate the minimum speed must she leave the ground
Using conservation of energy



Put the value into the formula




Hence, The minimum speed when she leave the ground is 6.10 m/s.
Answer: C (impulse acting on the object)
The momentum is defined as it is the impulse acting on the force . Change in momentum is known as Impulse. Impulse is used to increase or decrease the momentum of object.
From Newtons II law
F = m. a
= m. v/t <em>since a = rate of change of velocity.</em>
<em> </em>F . t = m . v
F . t is known as impulse momentum
Answer:B
Explanation: I think this is the answer