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3 years ago

5

you are standing on top of a 344 m tall building. A drone operated by your friend is headed straight down, at a speed of 37.0 m/

s. Just as the drone passes you, you release a tennis ball off the roof. How fast is the ball going when it passes the drone?

1 answer:

Kazeer [188]3 years ago

5 0

Answer:

v = 74.0m/s

Explanation:

Look at the photo.

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I need help asap pls

tigry1 [53]

no.9 indeed all matters are made out of atoms which is smaller than protons and neutrons

6 0

3 years ago

You are driving your car along a country road at a speed of 27.0 m/s. as you come over the crest of a hill, you notice a farm tr

Bezzdna [24]

speed of the car = 27 m/s

speed of truck ahead = 10 m/s

relative speed of car with respect to truck

$v_r = 27 - 10 = 17 m/s$

relative deceleration of car

$a_r = -7 m/s^2$

now the distance before they stop with respect to each other is given by

$v_f^2 - v_i^2 = 2 a d$

$0 - 17^2 = 2 *(-7)*d$

$d = 20.6 m$

so it will come at the same speed of truck after 20.6 m distance and hence it will not hit the truck as the distance of the truck is 25 m from car

Part b)

Distance traveled by car before it stops is given by

$v_f^2 - v_i^2 = 2 a s$

$0^2 - 27^2 = 2 * (-7)* s$

$s = 52.1 m$

so it will stop after it will cover total 52.1 m distance

Part c)

time taken by the car to stop

$v_f - v_i = at$

$0 - 27 = (-7) * t$

$t = 3.86 s$

now the distance covered by truck in same time

$d = 3.86 * 10 = 38.6 m$

now after the car will stop its distance from the truck is

$D = 25 + 38.6 - 52.1 = 11.5 m$

<em>so the distance between them is 11.5 m</em>

6 0

3 years ago

In an open system, the vapor pressure is equal to the outside air pressure. true false

Anvisha [2.4K]

False if the pressure is in an open system it could not be equal to the outside

8 0

4 years ago

Read 2 more answers

An unknown material, m1 = 0.49 kg, at a temperature of T1 = 92 degrees C is added to a Dewer (an insulated container) which cont

erastova [34]

Answer:

$c_u=1540.5J/kg^{\circ}K$

Explanation:

We know that heat relates to mass, specific heat and variation of temperature experimented because of this heat through the equation $Q=mc\Delta T=mc(T_f-T_i)$ . The heat released by the unknown material is absorbed by water, so we have $Q_u=-Q_w$ , and we can write:

$m_uc_u(T_{uf}-T_{ui})=-m_wc_w(T_{wf}-T_{wi})$

Since thermal equilibrium is reached we know that $T_{cf}=T_{wf}=T_f=31^{\circ}C=304^{\circ}K$ , where we have added $273^{\circ}$ to convert the temperature from Celsius to Kelvin, as <em>we must do</em>. Since we want the specific heat of the unknown material, we do:

$c_u=-\frac{m_wc_w(T_f-T_{wi})}{m_u(T_f-T_{ui})}$

Which for our values is:

$c_u=-\frac{(1.1kg)(4186J/kg^{\circ}K)((304^{\circ}K)-(294^{\circ}K))}{(0.49kg)((304^{\circ}K)-(365^{\circ}K))}=1540.5J/kg^{\circ}K$

3 0

3 years ago

During a race, a runner runs at a speed of 6 m/s. 2 seconds later, she is running at a speed of 10 m/s. What is the runner’s acc

igor_vitrenko [27]

Remember what acceleration is? It's how fast the speed is changing over a period of time.

$a = \frac{dv}{dt}$

So in dt = 2 secs, she sped up from 6 to 10 m/s and so dv = (10-6) m/s.

Now that you know dv and dt, you can calculate the acceleration a!

5 0

3 years ago