Answer:
The change in momentum of the car is 30,000 kg m/s
Explanation:
Given,
The force exerted on the car to slow down, F = 7500 N
The time period of force, t = 4 s
The rate of change of momentum of the object is equal to the force acting on it.
Therefore,
<em> (mv - mu) / t = F</em>
Where v and u are the final and initial velocity of the car. The change in momentum of the car,
mv - mu = F x t
= 7500 x 4
= 30,000 kg m/s
Hence the change in momentum of the car is 30,000 kg m/s
The energy of a wave is directly proportional to the square of the D.Amplitude
the energy of a wave is given as
E = (0.5) (μ v t ) w² A²
where t = time
μ = mass per unit length of the string
v = wave propagation of velocity.
w = angular frequency
A = amplitude
E = energy of wave
From the equation , we see that
the energy of wave "E" is directly proportional to A².
hence the correct choice is D. Amplitude.
Answer:
Q = -52.56 nC
Explanation:
The electric field outside a spherical shell is given by

where:
Q is the net charge
r is the radius of the spherical shell and E is the electric field magnitude.
Given:
r = 0.725 m
since the field points radially toward the center of the sphere, E = -899 N/C.
k is a constant with a value = 8.99 x 109 Nm²/C².
∴

Q = -52.56 nC