Answer:
r = 4.747 cm and h = 9.4925 cm
Explanation:
We know that volume of a cylinder is given as:
V = πr²h
Also, surface area is given as;
S = 2πr² + 2πrh
Where r is radius and h is height
Now, we are told that the volume is 672 cm³
Thus, πr²h = 672
Making h the subject gives;
h = 672/πr²
Putting 672/πr² for h in the surface area equation gives;
S = 2πr² + 2πr(672/πr²)
Factorizing gives;
S = 2π[r² + 672/πr]
Differentiating to get first derivative gives;
S' = 2π[2r - (672/πr²)]
Equating to zero gives;
2π[2r - (672/πr²)] = 0
4πr - 1344/r² = 0
4πr = 1344/r²
r³ = 1344/4π
r³ = 106.95212175775
r = ∛106.95212175775
r = 4.747 cm
So, since h = 672/πr²
Then, h = 672/π(4.747)²
h = 9.4925 cm
Answer:
4. Energy can be created and destroyed
Explanation:
Reason being it tells you a part of the definition of energy while all the other answers tell you why the sun is not the only source of energy.
Answer:
6.78571 m/s
55.13387 Joules
Explanation:
= Velocity of squid = 2.5 m/s
= Velocity of water
= Mass of water = 1.75 kg
Mass of squid
Momentum of squid
As the momentum of the system is conserved
The speed of the water is 6.78571 m/s
Kinetic energy the squid creates is given by
Kinetic energy of the squid + Kinetic energy of water
Kinetic energy the squid creates by this maneuver is 55.13387 Joules
Answer:
The voltage of the generator is 88.53volts
Explanation:
The voltage across the RLC AC circuit will be the voltage across the generator. It is expressed as
V = IZ and
Z² = R² + (Xl-Xc)²
Z = √R² + (Xl-Xc)² where;
Z is the impedance that oppose the flow of current in the resistor, capacitor and inductor in the circuit
I is the total current = 0.312A
R is the resistance in the circuit = 280ohms
Xl is the inductive reactance = 508ohms
Xc is the capacitive reactance = 315ohms
Substituting to this parameters to get the impedance Z we have;
Z = √280²+(508-315)²
Z = √208²+(193)²
Z = √80,513
Z = 283.75ohms
The voltage V of the generator = current × impedance
V = 0.312×283.75
V = 88.53Volts
The voltage if the generator is 88.53volts
Answer:
-4714.28N
Explanation:
Given
- Mass of person, m= 55 kg
- Car speed initially ,u =30
- Car speed finally, v=0(car comes to a halt)
- Duration for the car to come halt,t=0.35 sec
This question is based on the concept of Impulse
Impulse is the force acting in a time interval(usually very short)
it is equal to force multiplied with time and also equal to change in momentum of body
⇒
Therefore the seat belt exerts a force of -4718.28N on the person
The<u> negative sign</u> signifies that seat belt exerts force in opposite direction of Force