PHYSICS
MIDDLE SCHOOL

withstand a stress of about 1.58 x 10° Pa be-

fore breaking.

Assume that a femur (thigh bone) is 0.54 m

long, and calculate the amount of compression

this bone can withstand before breaking.

Answer in units of mm.

Answer:

Answer: 4.74 mm

Explanation:

We can solve this problem with the following equation:

(1)

Where:

is the Young modulus for femur

is the stress (force applied per unit of transversal area ) on the femur

Being:

the compression the femur can withstand before breaking

is the length of the femur without compression

Writing the data in equation (1):

(2)

(3)

Isolating :

(4)

(5) This is the compression in meters

Converting this result to millimeters:

HIGH SCHOOL

You watch a distant lady driving nails into her front porch at a regular rate of 1 stroke per second. You hear the sound of the blows exactly synchronized with the blows you see. And then you hear one more blow after you see her stop hammering. How far away is she? The speed of sound is 340 m/s.

Answer:

340 meters

Explanation:

For this we have to use the formula of constant velocity motion:

Because you hear the blows exactly 1 per second. And you hear only one blow after she finished, the sound takes one second to get to you.

COLLEGE

A water wave of wavelength 859 cm travels a distance of 64 m in a time of 14 s. What is the period of the wave, in units of seconds?

Answer:

1.87 s

Explanation:

d = distance traveled by the water wave = 64 m

t = time taken to travel the distance = 14 s

= speed of water wave

Speed of water wave is given as

= 4.6 m/s

= wavelength of the wave = 859 cm = 8.59 m

T = period of the wave

period of the wave is given as

T = 1.87 s

COLLEGE

Gina is driving her car to work, but she’s stopped at a red light. When the light turns green, she presses the gas pedal and accelerates (speeds up) to move the car. Which of these statements is true the moment Gina presses the gas pedal? Assume the road is flat and level. A. The net force on the car is zero in the horizontal direction. B. The net force on the car is zero in the horizontal and the vertical directions. C. The net force on the car is greater than zero in the horizontal direction. D. The net force on the car is greater than zero in the vertical direction. E. The net force on the car is less than zero in the vertical direction.

Since car is initially at rest so at that position the net force on car in vertical as well as horizontal both direction is zero

but after lights are green the car will speed up in horizontal direction

so now we can say that

It will accelerate in horizontal direction

So now as per Newton's formula we have

so now the force in horizontal direction will become nonzero while in vertical direction car is still in equilibrium

So now we can say

so the correct answer will be

C. The net force on the car is greater than zero in the horizontal direction.

COLLEGE

PLEASE HELP CORRECT ANSWER GETS BRAINLIEST!! Describe how the Doppler effect supports the big bang theory

The Doppler effect determined and supported that the universe was expanding by measuring the Doppler effect in the light emitted from galaxies.

Hope this helps!

Hope this helps!