An object with a velocity of 15 m/s and has a kinetic energy of 1125 J, what is the mass of the object?

In this circuit the resistance R1 is 3Ω, R2 is 7Ω, and R3 is 7Ω. If this combination of resistors were to be replaced by a single resistor with an equivalent resistance, what should that resistance be?

Answer:

9.1Ω

Explanation:

The circuit diagram has been attached to this response.

(i) From the diagram, resistors R1 and R2 are connected in parallel to each other. The reciprocal of their equivalent resistance, say Rₓ, is the sum of the reciprocals of the resistances of each of them. i.e

$\frac{1}{R_X} = \frac{1}{R_1} + \frac{1}{R_2}$

=> $R_{X} = \frac{R_1 * R_2}{R_1 + R_2}$ ------------(i)

From the question;

R1 = 3Ω,

R2 = 7Ω

Substitute these values into equation (i) as follows;

$R_{X} = \frac{3 * 7}{3 + 7}$

$R_{X} = \frac{21}{10}$

$R_{X} = 2.1$ Ω

(ii) Now, since we have found the equivalent resistance (Rₓ) of R1 and R2, this resistance (Rₓ) is in series with the third resistor. i.e Rₓ and R3 are connected in series. This is shown in the second image attached to this response.

Because these resistors are connected in series, they can be replaced by a single resistor with an equivalent resistance R. Where R is the sum of the resistances of the two resistors: Rₓ and R3. i.e

R = Rₓ + R3

Rₓ = 2.1Ω

R3 = 7Ω

=> R = 2.1Ω + 7Ω = 9.1Ω

Therefore, the combination of the resistors R1, R2 and R3 can be replaced with a single resistor with an equivalent resistance of 9.1Ω

4 0

2 years ago

1)the car's engine power is 44000W. Explain this number in a physical sense

Ratling [72]

Answer:

1) It expresses the rate (top speed) at which it can move with time.

2) P = 20 W

3) h = 18 km

Explanation:

1) Power is the rate of transfer of energy.

⇒ Power = $\frac{Energy(or workdone)}{Time}$

i.e P = $\frac{E}{t}$

Thus a car's engine power is 44000W implies that the engine of the car can propel the car at this rate. This expresses the rate (top speed) at which it can move with time.

2) m = 400g = 0.4 kg

t = 20 s

h = 100m

g = 10 m/ $s^{2}$

P = $\frac{mgh}{t}$

= $\frac{0.4*10*100}{20}$

= $\frac{400}{20}$

P = 20 W

3) u = 600 m/s

g = 10 m/ $s^{2}$

From the third equation of free fall,

$V^{2}$ = $U^{2}$ - 2gh

V is the final velocity, U is the initial velocity, h is the height.

0 = $(600)^{2}$ - 2 x 10 x h

0 = 360000 - 20h

20h = 360000

h = $\frac{360000}{20}$

= 18000

h = 18 km

The maximum height of the bullet would be 18 km.

3 0

2 years ago

A bungee jumper feels weightless as she falls toward the earth.what accounts for her weightless feeling when she fall freely?1.

Ann [662]

The feel of weight comes due to the normal reaction force given by the support. Hence, the condition of weightlessness is when the normal reaction force becomes zero. So, during free fall there is no support which can provide the normal reaction. Hence, the bungee jumper feels weightless as she falls towards the earth because of the lack of support force that balances gravity.

Hence, the answer is 3.

8 0

2 years ago

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