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3 years ago

What is the average speed of a car that travels a distance of 10 km in 30 min?

Physics

1 answer:

Natali [406]3 years ago

4 0

Answer:

The average speed of a car is 20 km/h.

Explanation:

We have,

Distance covered by car is 10 km

Time taken by the car to cover that distance is 30 min. 30 min means 0.5 hours.

It is required to find the average speed of a car. It can be calculated using formula of average speed which is given by :

$v=\dfrac{d}{t}\\\\v=\dfrac{10\ km}{0.5\ h}\\\\v=20\ km/h$

So, the average speed of a car is 20 km/h.

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Question 10 (1 point)

torisob [31]

Answer:

It does not hit the students face because the speed of the balloon slows down as energy is lost through thermal.

Explanation:

3 0

3 years ago

A model rocket is launched directly upward at a speed of 16 meters per second from a height of 2 meters. The function f(t)=−4.9t

Crank

Answer:

$Hmax=15.06$ meters

Explanation:The question ask for the maximum value of the function f(t) which can be find by find the maxima of the function

The maxima of the function occurs when the slope is zero. i.e.

$\frac{df}{dt} =0\\\frac{df}{dt} =\frac{d}{dt} (-4.9t^2+16t+2)\\\frac{df}{dt} =-4.9*2t+16\\-9.8t+16=0\\t=16/9.8\\t=1.63 secs$

Hence the maxima occurs at t=1.63 seconds

The maximum value of f is

$f(1.63)=-4.9(1.63^2)+16(1.63)+2\\f(1.63)=15.06\\$

hence maximum height is found to be

$Hmax=15.06$ meters

8 0

3 years ago

A 50-g cube of ice, initially at 0.0°C, is dropped into 200 g of water in an 80-g aluminum container, both initially at 30°C.

MakcuM [25]

Answer:

b. 9.5°C

Explanation:

$m_i$ = Mass of ice = 50 g

$T_i$ = Initial temperature of water and Aluminum = 30°C

$L_f$ = Latent heat of fusion = $3.33\times 10^5\ J/kg^{\circ}C$

$m_w$ = Mass of water = 200 g

$c_w$ = Specific heat of water = 4186 J/kg⋅°C

$m_{Al}$ = Mass of Aluminum = 80 g

$c_{Al}$ = Specific heat of Aluminum = 900 J/kg⋅°C

The equation of the system's heat exchange is given by

$m_i(L_f+c_wT)+m_wc_w(T-T_i)+m_{Al}c_{Al}=0\\\Rightarrow 0.05\times (3.33\times 10^5+4186\times T)+0.2\times 4186(T-30)+0.08\times 900(T-30)=0\\\Rightarrow 1118.5T-10626=0\\\Rightarrow T=\dfrac{10626}{1118.5}\\\Rightarrow T=9.50022\ ^{\circ}C$

The final equilibrium temperature is 9.50022°C

4 0

3 years ago

Light waves travel in straight lines in all directions from the source of the light, unless

Ainat [17]

A. the medium through which the light travels changes.

Explanation:

Light waves will continue to travel in a straight line in all directions from their source unless the medium through which the light travels changes.

A change in medium causes light to exhibit different properties. Also, when light hits an obstacle, they can be diffracted.

The way light travels on crossing a boundary differs.
At the boundary between two medium, light can either be reflected back or refracted when they cross the medium
This will cause the light rays to bend towards or away from the normal depending on the properties of the medium.

Learn more:

Refraction brainly.com/question/12370040

#learnwithBrainly

6 0

3 years ago

Both the moon and the sun influence the tides on Earth. The moon has a much greater influence though. Why is that

3241004551 [841]

Because even though the moon is smaller, therefore a weaker gravitational pull, the moon is much closer to the earth than the sun, thus having a greater gravitational pull

3 0

3 years ago