How can we avoid injuries in school or community when engaging in physical activities?

What is the speed of sound in air at 50°F (in ft/s)?

gizmo_the_mogwai [7]

Answer:

Speed of air = 1106.38 ft/s

Explanation:

Speed of sound in air with temperature

$v_{air}=331.3\sqrt{1+\frac{T}{273.15}} \\$

Here speed is in m/s and T is in celcius scale.

T = 50°F

$T=(50-32)\times \frac{5}{9}=10^0C \\$

Substituting

$v_{air}=331.3\sqrt{1+\frac{10}{273.15}}=337.31m/s \\$

Now we need to convert m/s in to ft/s.

1 m = 3.28 ft

Substituting

$v_{air}=337.31\times 3.28=1106.38ft/s \\$

Speed of air = 1106.38 ft/s

6 0

3 years ago

PLEASE HELP MEE

ExtremeBDS [4]

Answer:

<h2>work = mgh</h2><h2> = 125 × 2</h2><h2> = 250 joules</h2>

7 0

3 years ago

1.

lyudmila [28]

Answer:

$100m \div \frac{9 \: m}{1sec} = 11.11 \: sec \:$

I guess you can round it to 11 seconds.

Explanation:

Going with a speed 9m/s means you are going 9 meters in each second.

If you are going 9 meters in second how many seconds will it take to 100 meters?

Visually;

9 meters - - - 1 second

100 meters - - - ?seconds.

When you write like this 9 times ?seconds equal to 100 meters time 1 second. (you probably know this but just in case)

So to find ?second you multiply 100meters by 1 and divide it by 9 whixh will give you 11.1111 seconds whixh again I believe you can round it to 11.

(Kind of a) Proof;

If 9m * ?sec = 100 m * 1 sec

you send 9 meters to other side.

?sec = (100 m * 1 sec) ÷ 9m

Hope it was clear and it helps! Please let me know if you have any questions.

7 0

3 years ago

An 850-lb force is applied to a 0.15-in. diameter nickel wire having a yield strength of 45,000 psi and a tensile strength of 55

Sindrei [870]

Answer:

a)Yes will deform plastically

b) Will NOT experience necking

Explanation:

Given:

- Applied Force F = 850 lb

- Diameter of wire D = 0.15 in

- Yield Strength Y=45,000 psi

- Ultimate Tensile strength U = 55,000 psi

Find:

a) Whether there will be plastic deformation

b) Whether there will be necking.

Solution:

Assuming a constant Force F, the stress in the wire will be:

stress = F / Area

Area = pi*D^2 / 4

Area = pi*0.15^2 / 4 = 0.0176715 in^2

stress = 850 / 0.0176715

stress = 48,100.16 psi

Yield Strength < Applied stress > Ultimate Tensile strength

45,000 < 48,100 < 55,000

Hence, stress applied is greater than Yield strength beyond which the wire will deform plasticly but insufficient enough to reach UTS responsible for the necking to initiate. Hence, wire deforms plastically but does not experience necking.

6 0

3 years ago

If the photon scatters in the backward direction, what is the magnitude of the linear momentum of the electron just after the co

Strike441 [17]

Momentum is a vector quantity, and is always conserved. Whenever a collision occurs between two objects, the objects behave under the principle of conservation of momentum. Therefore, if an object moves in the direction opposite to its original direction after a collision, then this indicates that the momentum of the colliding object was greater than the object under consideration.

8 0

3 years ago