Answer:
the kinetic energy of body B is twice the kinetic energy of body A
Explanation:
The kinetic energy of a body is given by
K = ½ m v²
If two objects leave the same point, suppose that at the same height when they reach the ground they have the same velocity.
Therefore if the mass of body b is twice the mass of body A
= ½ (2 
) v²
K_{b} = 2 (½ m_{a} v²)
K_{b} = 2 K_{a}
therefore the kinetic energy of body B is twice the kinetic energy of body A
Answer:
Remains the same
Explanation:
The speed of waves of higher and lower frequency both will be same.
the speed of sound in a medium is constant and independent of it's frequency. Moreover, when the frequency changes wavelength changes accordingly, such that their product remains constant.
we know that
υ×λ = constant = velocity
υ= frequency
λ= wavelength.
Answer:
a) Wavelength of the ultrasound wave = 0.0143 m <<< 3.5m, hence its ability is not limited by the ultrasound's wavelength.
b) Minimum time difference between the oscillations = Period of oscillation = 0.00952 ms
Explanation:
The frequency of the ultrasound wave = 105 KHz = 105000 Hz. The speed of ultrasound waves in water ≈ 1500 m/s. Wavelength = ?
v = fλ
λ = v/f = 1500/105000 = 0.0143 m <<< 3.5m
This value, 0.0143m is way less than the 3.5m presented in the question, hence, this ability is not limited by the ultrasound's wavelength.
b) Minimum time difference between the oscillations = The period of oscillation = 1/f = 1/105000 = 0.00000952s = 0.00952 ms
Hope this helps!
For the work-energy theorem, the work needed to stop the bus is equal to its variation of kinetic energy:
where
W is the work
Kf is the final kinetic energy of the bus
Ki is the initial kinetic energy of the bus
Since the bus comes at rest, its final kinetic energy is zero:
, so the work done by the brakes to stop the bus is
And the work done is negative, because the force applied by the brake is in the opposite direction to that of the bus motion.
Answer:
1.63 N
Explanation:
F = GMm/r^2
= (6.67x10^-11)(10x10^5)(3x10^5) / 3.5^2
= 1.63 N ( 3 sig. fig.)
