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4 years ago

I tried looking at formulas, if you know the formula can you list it?

Physics

2 answers:

mash [69]4 years ago

8 0

Answer:

a. -10 m/s²

b. -15000 N

Explanation:

a. First, write which variables are given:

v₀ = 20 m/s

v = 0 m/s

t = 2 s

Next, identify the variable you're looking for.

Find: a

Determine which equation uses these variables. One trick is to find which variable isn't included in the problem, then find the equation that doesn't use that variable. In this case, we don't need displacement Δx. So the equation we should use is:

v = at + v₀

Plug in and solve:

(0 m/s) = a (2 s) + (20 m/s)

a = -10 m/s²

b. Force is mass times acceleration.

F = ma

F = (1500 kg) (-10 m/s²)

F = -15000 N

serg [7]4 years ago

5 0

Answer:y=mx+b

Explanation:

y=mx+b

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padilas [110]

Answer:

D. The cart is moving at a constant speed or velocity

Explanation:

Equilibrium is a state of body in which it is either at rest or moves with uniform velocity. The sum of forces acting on such a body is always zero and the sum of all the torques acting on it is also zero.

There are two types of equilibrium as follows:

Static Equilibrium: When a body is at rest it is said to be in static equilibrium.

Dynamic Equilibrium: When a body is moving with constant velocity, then it is said to be in dynamic equilibrium.

Hence, the correct option here will be:

<u>D. The cart is moving at a constant speed or velocity</u>

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3 years ago

What is the final velocity of a car that starts at 22 m/s and accelerates at 3.78 m/s for distance of 45 m

Pepsi [2]

v^2 = v0^2 +2ad v^2 = 22^2 + 2*3.78*45 = 824.2 v= √824.2 = 28.7 m/s

5 0

4 years ago

A student team is to design a human powered submarine for a design competition. The overall length of the prototype submarine is

Allushta [10]

Answer:

a) The speed is 61.42 m/s

b) The drag force is 10.32 N

Explanation:

a) The Reynold´s number for the model and prototype is:

$Re_{m} =\frac{p_{m}V_{m}L_{m} }{u_{m} }$

$Re_{p} =\frac{p_{p}V_{p}L_{p} }{u_{p} }$

Equaling both Reynold's number:

$\frac{p_{p}V_{p}L_{p} }{u_{p} }=\frac{p_{m}V_{m}L_{m} }{u_{m} }$

Clearing Vm:

$V_{m} =\frac{p_{p}V_{p}L_{p} u_{m} }{u_{p} p_{m} L_{m} }=\frac{999.1*0.56*8*1.849x10^{-5} }{1.138x10^{-3}*1.184*1 } =61.42m/s$

b) The drag force is:

$\frac{F_{Dm} }{p_{m}V_{m}^{2}L_{m}^{2} } =\frac{F_{Dp} }{p_{p}V_{p}^{2}L_{p}^{2} } \\F_{Dp} =\frac{F_{Dp}p_{p}V_{p}^{2}L_{p}^{2} }{p_{m}V_{m}^{2}L_{m}^{2} } \\F_{Dp}=\frac{2.3*999.1*0.56^{2} *8^{2} }{1.184*61.42^{2}*1^{2} } =10.32N$

6 0

3 years ago

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In your own words, explain how the red shift in the spectrum of objects in space provide evidence for the Big Bang Theory.

kondaur [170]

The evidence that the universe is expanding comes with something called the red shift<span> of light. Light travels to Earth from other galaxies. As the light from that galaxy gets closer to Earth, the distance between Earth and the galaxy increases, which causes the wavelength of that light to get longer.</span>

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3 years ago

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Observer 1 rides in a car and drops a ball from rest straight downward, relative to the interior of the car. The car moves horiz

steposvetlana [31]

a) 10.5 m/s

While for observer 1, in motion with the car, the ball falls down straight vertically, according to observer 2, which is at rest, the ball is also moving with a horizontal speed of:

$v_x = 3.80 m/s$

As the ball falls down, it also gains speed along the vertical direction (due to the effect of gravity). The vertical speed is given by

$v_y = u_y + gt$

where

$u_y =0$ is the initial vertical speed

g = 9.8 m/s^2 is the acceleration of gravity

t is the time

Therefore, after t = 1.00 s, the vertical speed is

$v_y = 0 + (9.8)(1.00)=9.8 m/s$

And so the speed of the ball, as observed by observer 2 at rest, is given by the resultant of the horizontal and vertical speed:

$v=\sqrt{v_x^2 +v_y^2}=\sqrt{(3.8)^2+(9.8)^2}=10.5 m/s$

b) $\theta = -68.8^{\circ}$

As we discussed in previous part, according to observer 2 the ball is travelling both horizontally and vertically.

The direction of travel of the ball, according to observer 2, is given by

$\theta = tan^{-1} (\frac{v_y}{v_x})=tan^{-1} (\frac{-9.8}{3.8})=-68.8^{\circ}$

We have to understand in which direction is this angle measured. In fact, the car is moving forward, so $v_x$ has forward direction (we can say it is positive if we take forward as positive direction).

Also, the ball is moving downward, so $v_y$ is negative (assuming upward is the positive direction). This means that the direction of the ball is forward-downward, so the angle above is measured as angle below the positive horizontal direction:

$\theta = -68.8^{\circ}$

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3 years ago