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3 years ago

22. A race car accelerates from 0.0 m/s to 5 m/s with a displacement of 2.5 m. What is the

Physics

1 answer:

yanalaym [24]3 years ago

6 0

Answer:

Option A

$5 m/s^{2}$

Explanation:

From fundamental equation of motion

$v^{2}=u^{2}+2as$ where v is the final velocity, u is the initial velocity, a is the acceleration of the body and s is the displacement.

Since the initial velocity is zero

$v^{2}=2as$

Making acceleration, a the subject of the formula then

$a=\frac {v^{2}}{2s}$

Substituting 5 m/s for v and 2.5 m for s then

$a=\frac {5^{2}}{2\times 2.5}=5 m/s^{2}$

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A square is 1.0 m on a side. Point charges of +4.0 μC are placed in two diagonally opposite corners. In the other two corners ar

finlep [7]

Answer:

B) 1.0 × 10^5 V

Explanation:

Electric Potential Due To Point Charges

The electric potential produced from a point charge Q at a distance r from the charge is

$\displaystyle V=k\frac{Q}{r}$

The total electric potential for a system of point charges is equal to the sum of their individual potentials. This is a scalar sum, so direction is not relevant.

We must compute the total electric potential in the center of the square. We need to know the distance from all the corners to the center. The diagonal of the square is

$d=\sqrt2 a$

where a is the length of the side.

The distance from any corner to the center is half the diagonal, thus

$\displaystyle r=\frac{d}{2}=\frac{a}{\sqrt{2}}$

$\displaystyle r=\frac{1}{\sqrt{2}}=0.707\ m$

The total potential is

$V_t=V_1+V_2+V_3+V_4$

Where V1 and V2 are produced by the +4\mu C charges and V3 and V4 are produced by the two opposite charges of $\pm 3\mu\ C$ . Since all the distances are equal, and the charges producing V3 and V4 are opposite, V3 and V4 cancel each other. We only need to compute V1 or V2, since they are equal, but they won't cancel.

$\displaystyle V_1=V_2=k\frac{Q}{r}=9\times 10^9 \frac{4\times 10^{-6}}{0.707}$

$V_1=V_2=50912\ V$

The total potential is

$V_t=50912\ V+50912\ V=1\times 10^5\ V$

$\boxed{V_t=1\times 10^5\ V}$

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3 years ago

When jumping down from a table to the ground, it is helpful to bend your knees when you hit the ground because...

forsale [732]

Answer:

This reduces the average force applied during the landing process/ or you can say it reduces the impact your body takes.

Explanation:

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3 years ago

Calculate the final speed of a 110-kg rugby player who is initially running at 8.00 m/s but collides head-on with a padded goalp

Contact [7]

The answer is -0.8 m/s. We know acceleration is the average of final minus initial velocity over time (a = (vf-v0)/t). We also know that Force is equal to Mass times Acceleration (F = ma). Using our force equation, we know that the acceleration we get is negative 8.8 (-8.8). The force is acting in the opposite direction of the rugby player, hence the negative sign. From there, plug in that number for a in the velocity equation, and solve for vf, as v0 and t are known. We get 0.8 m/s in the opposite direction that the player was running.

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3 years ago

Assume the space shuttle's main engines produce 764,576 newtons of thrust, and the shuttle has a mass of 78,018 kg. Why does the

Nady [450]

Weight of anything = (mass) x (gravity in the place where the thing is)

Weight of anything on Earth = (mass) x (9.81 m/s²)

Weight of the shuttle = (78,018 kg) x (9.81 m/s²)

Weight of the shuttle, on Earth = 765,357 Newtons

Thrust of main engines = 764,576 Newtons

Are you starting to see the problem yet ?

The weight of the whole thing standing on the launch pad is 751 Newtons more than the maximum thrust of the main engines, and the engines can't lift it ! Even with all throttles wide open, the main engines alone would need about 175 more pounds of thrust to budge that load off the ground. Even with the pedal to the metal, with flame and smoke belching out and covering the whole launch complex, the shuttle would just sit there and never leave the pad.

Well, no. That's not exactly what would happen. As the fuel in the main monster fuel tank is burned, the weight decreases. So it would actually happen like this: After the man announced "Zero ! We have ignition ! All engine running !", the ship would just sit there on the pad ... at first. It would go nowhere and not even wiggle, UNTIL the first 175 pounds of fuel got burned without accomplishing anything. The ship would then be 175 pounds lighter. At that point, the weight would be exactly equal to the thrust of the main engines, and the vertical forces on the ship would be balanced. Then, as MORE fuel continued to be wasted and the weight continued to decrease, the main engines could just begin to lift the ship off the pad.

So the correct answer is choice-D . It tells the whole story, quicker than I can tell it.

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3 years ago

What is the momentum of a ten ton truck which is sitting still?

ANTONII [103]

The momentum of the truck is given by:

p = mv

p = momentum, m = mass, v = velocity

There isn't too much work to do here; the truck is at rest, therefore its velocity is 0. This means the product of m and v is 0, giving the momentum as 0.

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3 years ago