Mechanical waves require medium
Answer:
Explanation:
A )
v² = u² + 2 a s
u = 0
s = 2.5
a = 9.8
v² = 2 x 9.8 x 2.5 = 49
v = 7 m /s
B )
time required to fall by first 2.5 m , t₁
s = 1/2 a t₁²
2.5 = .5 x 9.8 t₁²
t₁ = .714 s
time required to fall by 10 m
s = 1/2 a t₂²
10 = .5 x 9.8 t₂²
t₂ = 1.43 s
time required to fall by last 7.5 m
= t₂ - t₁
= 1.43 - .714
= .72 s
C )
time taken by second = .72 s
For second let initial velocity required be u
s = ut + 1/2 g t²
10 = u x .72 + .5 x 9.8 x .72²
10 = u x .72 + 2.54
u = 10.36 m /s
Q: An appliance with a 20 Ω resistor has a power rating of 15.0 W. Find the maximum current which can flow safely through the appliance g
Answer:
0.866 A
Explanation:
From the question,
P = I²R............................. Equation 1
Where P = power, I = maximum current, R = Resistance.
Make I the subject of the equation
I = √(P/R).................... Equation 2
Given: P = 15 W, R = 20 Ω
Substitute these values into equation 2
I = √(15/20)
I = √(0.75)
I = 0.866 A
Hence the maximum current that can flow safely through the appliance = 0.866 A
Answer:
#See solution for details.
Explanation:
Newton's Second law of motion states that :- the rate of change of momentum is directly proportional to the force applied on an object or system..
The force applied on an object of mass m is directly proportional to the product of mass and acceleration:
-Let be the initial momentum and be the final momentum.
#also let be the initial velocity and the final.
Momentum,:
#where k is the constant of proportionality. Given the direct proportion, k=1.
#The unit is in kgm/s but usually equated to N, 1kgm/s=1N