Answer:
The fraction of kinetic energy lost in the collision in term of the initial energy is 0.49.
Explanation:
As the final and initial velocities are known it is possible then the kinetic energy is possible to calculate for each instant.
By definition, the kinetic energy is:
k = 0.5*mV^2
Expressing the initial and final kinetic energy for cars A and B:


Since the masses are equals:

For the known velocities, the kinetics energies result:




The lost energy in the collision is the difference between the initial and final kinectic energies:


Finally the relation between the lost and the initial kinetic energy:


Compared with the amount of current in the filament of a lamp, the amount of current in the connecting wire is
D. the same.
As per the rule, the amount of current in devices connected in series is equal. here in the given situation , the wire is in series with the filament. that is the reason that the current in filament and wire is same.
hence the correct choice is D)
Answer:
Explanation:
- The radio waves have a fixed relationship between the propagation speed (the speed of light in vacuum), the frequency and the wavelength, as follows:
- v = c = λ*f
where c= speed of light in vacuum = 3*10⁸ m/s, λ = wavelength =
4.92*10⁷ m.
Solving for f, we get the frequency of the radio waves:
f = 6.1 Hz
- Now, from the Hooke's law, we know that the mass attached at the end of the spring oscillates with an angular frequency defined by a fixed relationship between the spring constant k and the mass m, as follows:

- Now, we know that there exists a fixed relationship between the angular frequency and the frequency, as follows:
- We also know that f in (2) is the same that we got for the radio waves, so replacing (2) in (1), and rearranging terms, we can solve for k, as follows:

Answer:
Force A=-−2,697.75 N
Force B=13, 488.75 N
Explanation:
Taking moments at point A, the sum of clockwise and anticlockwise moments equal to zero.
25 mg-20Fb=0
25*1100g=20Fb
Fb=25*1100g/20=1375g
Taking g as 9.81 then Fb=1375*9.81=13,488.75 N
The sum of upward and downward forces are same hence Fa=1100g-1375g=-275g
-275*9.81=−2,697.75. Therefore, force A pulls downwards
Note that the centre of gravity is taken to be half the whole length hence half of 50 is 25 m because center of gravity is always at the middle
Answer:
Explanation:
As we know that the ball is projected upwards so that it will reach to maximum height of 16 m
so we have

here we know that

also we have

so we have


Now we need to find the height where its speed becomes half of initial value
so we have

now we have




