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3 years ago

A crash test dummy is inside a test car moving at 55 km/h. How fast is the dummy moving relative to the seat he is sitting in?

2 answers:

8 0

The situation is exactly the same as YOUR speed relative to the seat you're sitting in, aboard the passenger jet flying at 500 mph with you in it.

kvasek [131]3 years ago

7 0

The dummy is moving with a speed 0 km/h relative to the seat in which it is sitting.

If the relative speed was non-zero, the dummy would move away from its seat, which contradicts the problem formulation.

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The plates of a parallel-plate capacitor are maintained with a constant voltage by a battery as they are pushed together, withou

UNO [17]

Answer:

<em>The amount of charge increases.</em>

Explanation:

For a capacitor that has its plates still connected to a battery, the voltage on the capacitor remains constant. If the distance between the two plates of this capacitor is decreased, the capacitance will increase, and then the charge on the plate will increase in accordance with the relationship

Q =CV

From this relationship, if V is held constant, then Q has to increase for C to increase also.

7 0

4 years ago

An insulated Thermos contains 140 cm3 of hot coffee at 85.0°C. You put in a 15.0 g ice cube at its melting point to cool the cof

Pavel [41]

Answer:

$T = 69^o C$

Explanation:

Here at thermal equilibrium we can say that thermal energy given by Hot coffee is equal to the thermal energy absorbed by ice cubes

So here we have

$Q_{ice} = Q_{coffee}$

now since ice cubes are added into coffee when it is at melting temperature

So here we can say that final temperature of coffee is T degree C

Now we have

$m_1L + m_1c_1\Delta T_1 = m_2c_2\Delta T_2$

here we have

$m_1 = 15 gram$

L = 333 kJ/kg = 333 J/g[/tex]

$c_1 = c_2 = 4186 J/kg C = 4.186 J/g C$

$\Delta T_1 = T - 0$

$\Delta T_2 = 85 - T$

now we have

$15(333) + 15(4.186)(T - 0) = 140(4.186)(85 - T)$

$4995 + 62.79T = 49813.4 - 586.04T$

$648.83 T = 44818.4$

$T = 69^o C$

6 0

3 years ago

What is velocity in science

katovenus [111]

Answer:

Velocity is the rate at which the position changes. The average velocity is the displacement or position change (a vector quantity) per time ratio.

Hope this helps! ^-^

8 0

3 years ago

Read 2 more answers

PLZZZZZZZZZ HELPPPPP. BRAINLEST GIVEN What is a force of attraction between an object and the earth due to gravity?

kotykmax [81]

Answer:

acceleration due to gravity: -9.8 m/s^2

Fg=mass of object*(-9.8)

Explanation:

This is a pretty vague question, but I'll answer as best I can.

All matter has gravity. YOU have gravity, although your gravitational pull is small. So, the force of attraction between the Earth and an object on Earth is modeled as

Force of gravity=(Gravitational constant*mass of object 1*mass of object 2)/distance between objects squared

Note that distance between an object on Earth and Earth is the radius of Earth (distance to Earth's core/center of mass)

6 0

3 years ago

Imagine that treble sounds could travel at 400 m/s, but bass sounds traveled at only 300 m/s. If sound actually behaved that way

kirza4 [7]

Answer:

$\Delta t = 0.1s$

Explanation:

We need to calculate the difference between the times the waves from the bass sounds ( $t_b$ ) and treble sounds ( $t_t$ ) take to reach us, that is, $\Delta t = t_b-t_t$ .

Since $v=\frac{d}{t}$ , then $t=\frac{d}{v}$ and we can write:

$\Delta t = t_b-t_t=\frac{d}{v_b} - \frac{d}{v_t}=d(\frac{1}{v_b} - \frac{1}{v_t})=(120m)(\frac{1}{300m/s} - \frac{1}{400m/s})=0.1s$

4 0

3 years ago