All categories

4 years ago

Only need help with question 5

Physics

1 answer:

yarga [219]4 years ago

8 0

Please look up the answer on Brainly before answering again.

For car A: y=20x-200 A moves 20 meters every second x, and starts 200m behind BFor Car B: y= 15x B moves 15 meters every second and starts at basisSet two equations equal to each other to find time x where they meet:20x - 200 = 15x200 = 5x x= 40A moves 20 meters every second:20x40=800m

You might be interested in

The _______ is responsible for absorbing the most UV radiation.

Lorico [155]

_____Mesosphere_____

5 0

3 years ago

Read 2 more answers

What happens to the gravitational force between two objects as the objects move closer together?

zavuch27 [327]

Answer:

The Gravity gets stronger

Explanation:

Newtons laws of motion.

3 0

3 years ago

What is the density of 25 grams

Karolina [17]

"Density" is the ratio of two numbers ... the mass AND the volume of a piece of some material.

If you only have one number, then the density of it is like one scis, or one tweez, or the sound of one hand clapping, or one pant.

5 0

3 years ago

26. The problem with calculating the speed of an object simply by dividing distance by time is

Gekata [30.6K]

Answer:

We obtain the average velocity instead of the instantaneus velocity.

Explanation:

The problem with calculating speed in this way is that an average speed is being calculated and not an instantaneous speed at a given point.

$V_{average} =\frac{x}{t} \\where:\\x = distance\\t = interval of time$

To calculate the instantaneous speed, a very small space interval must be measured at a given time.

8 0

3 years ago

A rock is thrown upward from the top of a 30 m building with a velocity of 5 m/s. Determine its velocity (a) When it falls back

Kobotan [32]

Answer:

a) 5 m/s

b) 17.8542 m/s

c) 24.7212 m/s

0.229

Explanation:

t = Time taken

u = Initial velocity = 5 m/s

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.81 m/s²

$v=u+at\\\Rightarrow 0=5-9.81\times t\\\Rightarrow \frac{-5}{-9.81}=t\\\Rightarrow t=0.51 \s$

$s=ut+\frac{1}{2}at^2\\\Rightarrow s=5\times 0.51+\frac{1}{2}\times -9.81\times 0.51^2\\\Rightarrow s=1.27\ m$

So, the stone would travel 1.27 m up

$v^2-u^2=2as\\\Rightarrow v=\sqrt{2as+u^2}\\\Rightarrow v=\sqrt{2\times 9.81\times 1.27+0^2}\\\Rightarrow v=5\ m/s$

Velocity as the rock passes through the original point is 5 m/s

$s=ut+\frac{1}{2}at^2\\\Rightarrow 1.27=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{1.27\times 2}{9.81}}\\\Rightarrow t=0.51\ s$

Time taken to reach the original point is 0.51+0.51 = 1.02 seconds

So, total height of the rock would fall is 30+1.27 = 31.27 m

$s=ut+\frac{1}{2}at^2\\\Rightarrow 16.27=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{16.27\times 2}{9.81}}\\\Rightarrow t=1.82\ s$

Time taken by the stone to reach 15 m above the ground is 1.82+0.51 = 2.33 seconds

$v=u+at\\\Rightarrow v=0+9.81\times 1.82\\\Rightarrow v=17.8542\ m/s$

Speed of the ball at 15 m above the ground is 17.8542 m/s

$s=ut+\frac{1}{2}at^2\\\Rightarrow 31.27=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{31.27\times 2}{9.81}}\\\Rightarrow t=2.52\ s$

$v=u+at\\\Rightarrow v=0+9.81\times 2.52\\\Rightarrow v=24.7212\ m/s$

Speed of the stone just before it hits the street is 24.7212 m/s

F = Force

m = Mass = 100 kg

g = Acceleration due to gravity = 9.81 m/s²

s = Displacement = 4 km = 4000 m

P = Power = 1 hp = 745.7 Watt

t = Time taken = 20 minutes = 1200 seconds

μ = Coefficient of sliding friction

F = μ×m×g

⇒F = μ×100×9.81

W = Work done = F×s

P = Work done / Time

⇒P = F×s / t

$745.7=\frac{\mu \times 981\times 4000}{1200}\\\Rightarrow \mu=\frac{747.5\times 1200}{981\times 4000}\\\Rightarrow \mu=0.229$

Coefficient of sliding friction is 0.229

8 0

3 years ago