When you look at your speedometer and it reads 60 mph this is your instantaneous speed

vitfil [10]

Nevermind that one i dont know sorry

8 0

4 years ago

A blue car with mass mc = 427 kg is moving east with a speed of vc = 20 m/s and collides with a purple truck with mass mt = 1282

polet [3.4K]

Answer:8540 kg-g/s

Explanation:

Given

mass of blue car $m_c=427 kg$

velocity of blue car $v_c=20 m/s$

mass of the truck $m_t=1282 kg$

speed of truck $v_t=13 m/s$

After collision they stick and lock together

Let v be the velocity of combined system at angle \theta from vertical

Conserving momentum in east direction

$m_c\times v_c=(m_c+m_t)v\cos \theta$

$427\times 20 =1709\times v\cos \theta$ ------1

Conserving Momentum in Y direction

$m_t\times v_t=(m_c+m_t)v\sin \theta$

$1282\times 13 =1709\times v\sin \theta$ -------2

squaring and then adding 1 & 2 we get

$(8540)^2+(16666)^2=(1709)^2\cdot v^2$

v=10.95 m/s

initial momentum of car $=427\times 20=8540 kg-m/s$

6 0

4 years ago

A tuning fork vibrates at a frequency of 512 hertz

Naily [24]

Answer: The correct answer is " longitudinal wave with air molecules

vibrating parallel to the direction of travel".

Explanation:

In longitudinal wave, the particles vibrate parallel to the direction to the propagation of the wave. For example, sound wave is a longitudinal wave.

It needs a medium for its propagation. It can travel in solid, liquid and gas. It travel faster in solid in comparison to the liquid.

In the given problem, a tuning fork vibrates at a frequency of 512 hertz when struck with a rubber hammer. The sound produced by the tuning fork will travel through air. Here, a longitudinal wave with air molecules vibrating parallel to the direction of travel.

Therefore, the correct option is (1).

4 0

3 years ago

Read 2 more answers

17. A 120 m long train is moving in a direction with speed 20 m/s. A train B moving with 30

nydimaria [60]

Answer is D.

Speed:
Use relative speed to simplify the situation. Since the trains are moving in opposite directions, you can add the speeds and pretend the first train is stationary (moving at 0m/s) and the second train is moving at 50m/s.

Distance:
The front of the second train needs to travel 120m to get from the front to the back of the first train. When the front of the second train is at the back of the first train, the back of the second train is still 10m in front of the first train. The back therefore has to travel 130m to clear the first train. The total distance over which the trains are overlapping in this scenario is therefore 120 + 130 = 250m.

You have speed and you have distance so now just calculate time:

v = d / t
50 = 250 / t
t = 5s

4 0

3 years ago

A 1.45 kg falcon catches a 0.515 kg dove from behind in midair. What is their velocity after impact if the falcon's velocity is

True [87]

Answer:

Their velocity after the impact is 20.85 m/s.

Explanation:

Given that,

Mass of falcon, $m_1=1.45\ kg$

Mass of dove, $m_2=0.515\ kg$

Initial speed of the falcon, $u_1=26.5\ m/s$

Initial speed of the dove, $u_2=4.95\ m/s$

We need to find the final velocity after the impact. When the falcon catches the dove, it will becomes the case of inelastic collision. The conservation of momentum will be :

$m_1u_1+m_2u_2=(m_1+m_2)V\\\\V=\dfrac{m_1u_1+m_2u_2}{(m_1+m_2)}\\\\V=\dfrac{1.45\times 26.5+0.515\times 4.95}{(1.45+0.515)}\\\\V=20.85\ m/s$

So, their velocity after the impact is 20.85 m/s.

8 0

3 years ago