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3 years ago

Can someone please help me I don’t understand this

Physics

1 answer:

jolli1 [7]3 years ago

4 0

I think it’s a because it the only reasonable answer

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A truck traveling at a constant speed of 28 m/s passes a more slowly moving car. The instant the truck passes the car, the car b

choli [55]

Answer:

the velocity of car when it passes the truck is u = 16.33 m/s

Explanation:

given,

constant speed of truck = 28 m/s

acceleration of car = 1.2 m/s²

passes the truck in 545 m

speed of the car when it just pass the truck = ?

time taken by the truck to travel 545 m

time = $\dfrac{distance}{speed}$

time = $\dfrac{545}{28}$

time =19.46 s

velocity of the car when it crosses the truck

$S = ut + \dfrac{1}{2}at^2$

$545= u\times 19.46 + \dfrac{1}{2} \times 1.2 \times 19.46^2$

u = 16.33 m/s

the velocity of car when it passes the truck is u = 16.33 m/s

5 0

3 years ago

A professor sits at rest on a stool that can rotate without friction. The rotational inertia of the professor-stool system is 4.

Anestetic [448]

Answer:

$\omega=0.37 [rad/s]$

Explanation:

We can use the conservation of the angular momentum.

$L=mvR$

$I\omega=mvR$

Now the Inertia is I(professor_stool) plus mR², that is the momentum inertia of a hoop about central axis.

So we will have:

$(I_{proffesor - stool}+mR^{2})\omega=mvR$

Now, we just need to solve it for ω.

$\omega=\frac{mvR}{I_{proffesor-stool}+mR^{2}}$

$\omega=\frac{1.5*2.7*0.4}{4.1+1.5*0.4^{2}}$

$\omega=0.37 [rad/s]$

I hope it helps you!

5 0

4 years ago

if the kinetic and potential energy in a system or equal to the potential energy increases what happens as a result

8090 [49]

Answer:If the kinetic and potential energy in a system are equal, then the potential energy increases. ... Stored energy decreases. Energy of motion decreases. Total energy decreases

Explanation:

8 0

3 years ago

A cannon can make a maximum angle of 30 degrees with the horizon. What is the minimum speed of a cannon ball if it must clear a

stiks02 [169]

Answer:

28.3 m/s

Explanation:

From the question given above, the following data were obtained:

Angle of projection (θ) = 30°

Maximum height (H) = 10 m

Acceleration due to gravity (g) = 10 m/s²

Initial velocity (u) =?

Thus, we can obtain the minimum velocity cannon ball by using the following formula:

H = u²Sine² θ / 2g

10 = u² × (Sine 30)² / 2× 10

10 = u² × (0.5)² / 20

10 = u² × 0.25 / 20

10 = u² × 0.0125

Divide both side by 0.0125

u² = 10/ 0.0125

u² = 800

Take the square root of both side

u = √800

u = 28.3 m/s

Therefore, the minimum speed of the cannon ball is 28.3 m/s

8 0

3 years ago

A man pushes on a box at an angle of 30.0° with a force of 20.0 N and the box moves across the floor. Which of the following com

9966 [12]

Not sure what the given options are, but the answer is the horizontal component. This is given by Force x cos(angle), or Fcos(θ), where θ is the angle. In this case that would be 20cos(30) = 17.32N

6 0

4 years ago