Work is done on an object only if the force and displacement are _________

At a local swimming pool, the diving board is elevated h = 9.5 m above the pool's surface and overhangs the pool edge by L = 2 m

eimsori [14]

Answer:

1) The time it takes the diver to move off the end of the diving board to the pool surface, $t_w$ , is approximately 1.392 seconds

2) The horizontal distance from the edge of the pool to where the diver enters the water, $d_w$ , is approximately 5.76 meters

Explanation:

1) The given parameters are;

The height of the diving board above the pool's surface, h = 9.5 m

The length by which the diving board over hangs the pool L = 2 m

The speed with which the diver runs horizontally along the diving board, v₀ = 2.7 m/s

Taking $t_w$ = The time it takes the diver to move off the end of the diving board to the pool surface

Therefore, we have from the equation of free fall;

h = 1/2 × g × $t_w$ ²

Where;

g = The acceleration due to gravity = 9.81 m/s²

Substituting the values, gives;

9.5 = 1/2 × 9.81 × $t_w$ ²

$t_w$ = √(9.5/(1/2 × 9.81)) ≈ 1.392 s

The time it takes the diver to move off the end of the diving board to the pool surface = $t_w$ ≈ 1.392 s

2) The horizontal distance, $d_w$ , in meters from the edge of the pool to where the diver enters the water is given as follows;

$d_w$ = L + v₀ × $t_w$ = 2 + 2.7× 1.392 ≈ 5.76 m

∴ The horizontal distance from the edge of the pool to where the diver enters the water ≈ 5.76 meters.

7 0

3 years ago

You are standing on the bottom of a lake with your torso above water. Which statement is correct?

marishachu [46]

Answer:

c. There is a buoyant force that is proportional to the volume of your body that is below the level of the water.

Explanation:

Buoyancy can be defined as a force which is created by the water displaced by an object.

Simply stated, buoyancy is directly proportional to the amount of water that is being displaced by an object.

Hence, the greater the amount of water an object displaces; the greater is the force of buoyancy pushing the object up.

The buoyancy of an object is given by the formula;

$Fb = pgV$

$But, \; V = Ah$

$Hence, \; Fb = pgAh$

Where;

Fb = buoyant force of a liquid acting on an object.

g = acceleration due to gravity.

p = density of the liquid.

v = volume of the liquid displaced.

h = height of liquid (water) displaced by an object.

A = surface area of the floating object.

The unit of measurement for buoyancy is Newton (N).

In this scenario, you are standing on the bottom of a lake with your torso above water. Thus, there is a buoyant force that is proportional to the volume of your body that is below the level of the water.

3 0

3 years ago

Please help i give brainest but i need help asap

krok68 [10]

Answer:

Surface

Explanation:

Rayleigh Waves—surface waves that move in an elliptical motion, producing both a vertical and horizontal component of motion in the direction of wave propagation. Particle motion consists of elliptical motions (generally retrograde elliptical) in the vertical plane and parallel to the direction of propagation.

7 0

3 years ago

Describe how the ringing sound of a telephone travels through air

konstantin123 [22]

Sound waves, duh. What do u expect?

6 0

3 years ago

Read 2 more answers

A box of mass m = 23.0 kg is sliding along a horizontal frictionless surface at a speed vi = 7.10 m/s when it encounters a ramp

SashulF [63]

Answer:

d = 57.7 m

Explanation:

For this exercise we will use energy work theorems

W = ΔEm

Let's calculate the work of the rubbing force on the ramp

W = -fr d

The negative sign is because the force of friction opposes the movement

Newton's second law in the axis perpendicular to the ramp gives

N- W cos 21.8 = 0

N = mg cos 21.8

The equation for the force of friction is

fr = μN

fr = μ mg cos 21.8

Let's replace

W = - μ mg d cos 21.8

Let's look for energy in two points

Initial just before entering the ramp

Emo = K = ½ m v²

End the highest point where the body stops

$Em_{f}$ = U = mg y

We use trigonometry to find the height (y)

sin 21.8 = y / d

y = d sin 21.8

$Em_{f}$ = m g d sin 21.8

Let's replace

W = ΔEm = $Em_{f}$ - Em₀

- μ mg d cos 21.8 = mgd sin21.8 - ½ m v²

m g d (sin21.8 + μ cos 21.8) = ½ m v²

d = v² / (2 (sin21.8 + μ cos21.8))

d = 7.10² / (2 (sin21.8 + 0.0704 cos 21.8))

d = 50.41 /0.87345

d = 57.7 m

5 0

4 years ago

Work is done on an object only if the force and displacement are __________?