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3 years ago

In linear motion, what sign will the velocity have if an object is moving in reverse?

Physics

1 answer:

ratelena [41]3 years ago

7 0

in positive x direction sign is + (same for +y, +z)

going in reverse is minus.

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The titanium shell of an SR-71 airplane would expand when flying at a speed exceeding 3 times the speed of sound. If the skin of

Fed [463]

Answer:

The 10-meter long rod of an SR-71 airplane expands 0.02 meters (2 centimeters) when plane flies at 3 times the speed of sound.

Explanation:

From Physics we get that expansion of the rod portion is found by this formula:

$\Delta l = \alpha\cdot l_{o}\cdot (T_{f}-T_{o})$ (Eq. 1)

Where:

$\Delta l$ - Expansion of the rod portion, measured in meters.

$\alpha$ - Linear coefficient of expansion for titanium, measured in $\frac{1}{^{\circ}C}$ .

$l_{o}$ - Initial length of the rod portion, measured in meters.

$T_{o}$ - Initial temperature of the rod portion, measured in Celsius.

$T_{f}$ - Final temperature of the rod portion, measured in Celsius.

If we know that $\alpha = 5\times 10^{-6}\,\frac{1}{^{\circ}C}$ , $l_{o} = 10\,m$ , $T_{o} = 0\,^{\circ}C$ and $T_{f} = 400\,^{\circ}C$ , the expansion experimented by the rod portion is:

$\Delta l = \left(5\times 10^{-6}\,\frac{1}{^{\circ}C} \right)\cdot (10\,m)\cdot (400\,^{\circ}C-0\,^{\circ}C)$

$\Delta l = 0.02\,m$

The 10-meter long rod of an SR-71 airplane expands 0.02 meters (2 centimeters) when plane flies at 3 times the speed of sound.

4 0

3 years ago

If all else stays the same, which would cause an increase in the gravitational force on a space shuttle?

maks197457 [2]

"decreasing the distance of the space shuttle from Earth"

F = Gm(1)m(2)/R²
where R is the distance between the 2 objects, as it decreases, the force increases.

5 0

4 years ago

Read 2 more answers

PLEASE HELP A student climbs to the top of a press box where the cameras are. He wonders how many meters he is off of the ground

Feliz [49]

The height of the rail on top of the press box where the ball was dropped from is 11.025 m.

The given parameters:

Time of motion of the ball, t = 1.5 s
Let the height of the rail = h

<h3>Maximum height of fall;</h3>

The maximum height through which the ball was dropped from is calculated by applying second equation of motion;

$h = v_0_y t + \frac{1}{2} gt^2\\\\h = 0 + \frac{1}{2} gt^2\\\\h = \frac{1}{2} gt^2\\\\h = \frac{1}{2} (9.8) (1.5)^2\\\\h = 11.025 \ m$

Thus, the height of the rail on top of the press box where the ball was dropped from is 11.025 m.

Learn more about height of projectiles here: brainly.com/question/10008919

3 0

2 years ago

Nvm figured it out 1!!!1!3!2!1!3!

Natali [406]

Answer:

that's great, good job!

6 0

3 years ago

How batteries work? What are some possible mterials you could use to make your battery?

KATRIN_1 [288]

<span>Store chemical energy and then let it go as electrical energy when they are connected to a circuit.You can make batteries out of many things,like potatoes</span>

7 0

3 years ago