Applying conservation of momentum;

Where m1 = 80.0 kg; v1 =4.10 m/s; m2 = 130.0 kg; v2 = 0; mf = (80+130) kg; vf = ??
Therefore,
80*4.1 + 130*0 = 210*vf
vf = (80*4.1)/210 = 1.56 m/s
Answer: a) r= 4.82 * 10^-4 m ; b) 1420 V
Explanation: In order to solve this problem we have to take into account that potential for a sphere respec to V=0 at the infinity, which is given by:
V=k*Q/r where r is the radius of the drop
then we have
r=k*Q/V=9*10^9*38pC/710V= 4.82 * 10^-4 m
Finally if we join two drop to form one with the same radius but with twice charge the resultant potential is:
V= k*2*Q/(r)= 710*2= 1420 V
Answer:
E=1/2kmv^2
Explanation:
To get the formula...
The dimension of energy is [ M^1 L^2 T^-2]
The dimension of mass [M]=[M^1 L ^0T ^0]
Dimension of velocity[V]=[M ^0 L ^1 T ^−1]
Let [E]=k[M] ^x[V] ^y
K is constant and it remain a dimensionless quantity.
Therefore, M ^1L ^2T ^−2]=k[M ^1L ^0T ^0] x[M ^0L ^1 T ^−1] y
So, x=1,y=2
E= Kmv^2
K=1/2
Therefore E is 1/2kmv^2.
Answer:
Angle of diffraction for second order maxima is θ = 18.941°
Explanation:
From the question it is given that
wavelength of incident light = λ = 541 nm = 541 x 
order of maxima = n =2
diffraction grating has 600 lines per mm
⇒ distance between two slit is
= 1.66 x
m
using the relation of Braggs diffraction formula i.e.,
2dsinθ = nλ ..................................(1)
where, d = distance between two lines of grating
θ is the angle of diffraction
n= order of maxima
λ is the intensity of incident photon
on substituting the respected values in relation (1) we get,
2 x 1.66 x
m sinθ = 2 x 541 x 
⇒ sinθ = 0.3246
⇒ θ =
= 18.941 °
Explanation:
When the wire is connected to a battery, the compass needle moves and changes its position. This happens because the needle magnetizes the copper wire, thus, creating a force.
While the current in the wire produces a magnetic field and exerts a force on the needle. The insulation on the wire becomes energized and exerts a force on the needle. Hence, the compass needle moves and changes its position.