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3 years ago

A car travels at an average speed of 60 km / h for 15 minutes. How far does the car travel in 15 minutes?

Physics

1 answer:

salantis [7]3 years ago

6 0

Answer:

15km

Explanation:

Given parameters:

Average speed = 60km/hr

Time taken = 15min

Unknown:

Distance = ?

Solution:

The distance traveled can de derived using the expression below;

Distance = Average speed x time taken

Now let us convert the time to hr;

60min = 1hr

15min = $\frac{15}{60}$ = 0.25hr

Distance = 60km/hr x 0.25hr = 15km

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A circuit has two 4Ω resistors in series with each other. What is the total resistance?

Paha777 [63]

Answer: 8Ω

Explanation:

Since there are two resistors of 4Ω

connected in series, the total resistance (Rtotal) of the circuit is the sum of each resistance.

i.e Rtotal = R1 + R2

R1 = 4Ω

R2 = 4Ω

Rtotal = ?

Rtotal = 4Ω + 4Ω

Rtotal = 8Ω

Thus, the total resistance of the circuit is 8Ω

3 0

3 years ago

A hockey player swings her hockey stick and strikes a puck. According to Newtons 3rd law of motion which of the following is a r

Korvikt [17]

Complete Question:

A hockey player swings her hockey stick and strikes a puck. According to Newton’s third law of motion, which of the following is a reaction to the stick pushing on the puck?

A. the puck pushing on the stick .

B. the stick pushing on the player .

C. the player pushing on the stick .

D. the puck pushing on the player.

Correct Option:

According to Newton’s third law of motion the puck pushing on the stick is a reaction to the stick pushing on the puck.

Option: A

Explanation:

As when the hockey exert force on the puck (which is a flat ball basically used in ice hockey) then this action by hockey will receive equal and opposite reaction by puck. Thus when the stick is pushing on the this flat ball, then puck also push the stick. This is understood by newton's third law pf motion, where action and reaction forces are subject of discussion, displaying their is pair of forces applied among the interacting objects. This form is observed more practically in life and very frequent.

3 0

3 years ago

Which of the following statements are true?

inessss [21]

Answer:

a. If an object's speed is constant, then its acceleration must be zero.

FALSE

As we know that acceleration is defined as the rate of change in velocity

$a = \frac{d\vec v}{dt}$

so we can not say anything about the acceleration when speed is given to as and no information is given about velocity

b. If an object's acceleration is zero, then its speed must be constant.

TRUE

As we know that acceleration is defined as the rate of change in velocity

$a = \frac{d\vec v}{dt}$

Since we know that if acceleration is 0 then velocity must be constant and hence speed is also constant

c. If an object's velocity is constant, then its speed must be constant.

TRUE

Since velocity is constant then it shows that its magnitude and direction both are constant so its speed is also constant.

d. If an object's acceleration is zero, its velocity must be constant.

TRUE

As we know that acceleration is defined as the rate of change in velocity

$a = \frac{d\vec v}{dt}$

Since we know that if acceleration is 0 then velocity must be constant

e. If an object's speed is constant, then its velocity must be constant.

FALSE

Speed is just the magnitude so we can not say about its direction and hence if speed is constant then velocity may or may not change

7 0

3 years ago

In si units, the electric field in an electromagnetic wave is described by ey = 104 sin(1.40 107x − ωt). (a) find the amplitude

melamori03 [73]

Answers:
(a) $B_o = 0.3466$ μT
(b) $\lambda = 0.4488$ μm
(c) f = $6.68 * 10^{14}Hz$

Explanation:
Given electric field(in y direction) equation:
$E_y = 104sin(1.40 * 10^7 x -\omega t)$

(a) The amplitude of electric field is $E_o = 104$ . Hence

The amplitude of magnetic field oscillations is $B_o = \frac{E_o}{c}$
Where c = speed of light

Therefore,
$B_o = \frac{104}{3*10^8} = 0.3466$ μT (Where T is in seconds--signifies the oscillations)

(b) To find the wavelength use:
$\frac{2 \pi }{\lambda} = 1.40 * 10^7$
$\lambda = \frac{2 \pi}{1.40} * 10^{-7}$
$\lambda = 0.4488$ μm

(c) Since c = fλ
=> f = c/λ

Now plug-in the values
f = (3*10^8)/(0.4488*10^-6)
f = $6.68 * 10^{14}Hz$

6 0

3 years ago

A car accelerate from a stop to 27 m/sec in 5 seconds. What was the car's acceleration?

Furkat [3]

The acceleration should 5.4 m/s^2

4 0

3 years ago