Answer:
a) 
b) 
Explanation:
Given:
mass of the ball, 
horizontal velocity of the ball, 
mass of the person, 
a)
<u>Using the law of conservation of momentum:</u>



b)
Given:
- rebound velocity of the ball,

Using conservation of momentum,



There is no illustration of the problem provided but I'll attempt to provide an answer.
The relationship between the electric potential difference between two points and the average strength of the electric field between those two points is given by:
║E║ = ΔV/d
║E║ is the magnitude of the average electric field, ΔV is the potential difference between A and B, and d is the distance between A and B.
We are given the following values:
║E║= 10N/C
d = 3m
Plug these values in and solve for ΔV
10 = ΔV/3
ΔV = 30V
Because of the different speeds..
Answer:
33 kg m/s
Explanation:
The momentum of an object is given by:

where
m is the mass of the object
v is the velocity of the object
In this problem, the total mass of the child and the wagon is m =22 kg, while the velocity is v = 1.5 m/s, therefore the momentum is

Answer:
b. 12.5 mAs, 70 kVp
Explanation:
The given parameter are;
The initial exposure factors := 10 mAs and 70 kVp
The initial Grid Ratio, G.R.₁ = 8:1
The Grid Ratio with which the radiographer desires to increase the scatter absorption, G.R.₂ = 12:1
Given that the lead content in the 12:1 grid, is higher than the lead content in 8:1 grid and that 12:1 grid needs more mAs to compensate, and provides a higher image contrast, the amount of extra mAs is given by the Grid Conversion Factors, GCF, as follows;
The GCF for G.R. 8:1 = 4
The GCF for G.R. 12:1 = 5
Therefore, given that the mAs used by the radiographer for 8:1 Grid Ratio is 10 mAs, the mAs required for a G.R. of 12:1 in order to maintain the same exposure is given as follows;
mAs for G.R. of 12:1 = 10 mAs × 5/4 = 12.5 mAs
Therefore the new exposure factors are;
12.5 mAs, 70 kVp