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2 years ago

Person X pushes twice as hard against a stationary brick wall as person Y. Which one of the following statements is correct?

Physics

1 answer:

Mrac [35]2 years ago

6 0

Answer:

D) Both do zero work

Explanation:

The work done by a force is given by:

$W=Fd cos \theta$

where

F is the force applied

d is the displacement

$\theta$ is the angle between the direction of the force and the displacement

From the formula, we notice that work is done online when the displacement is non-zero, so when the object is moving.

In this problem, the wall is stationary: this means that the displacement is zero, d = 0, so no work is done.

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You are flying a hang glider at 14 mph in the northeast direction (45°). The wind is blowing at 4 mph from due north.

Afina-wow [57]

Answer:

a) 17.05 mph

b) 54.7° northeast direction

c) 10.71 mph

The direction is -22.58° relative to the east.

To head northeast, you must either increase your gliding speed or increase your angle relative to the x-axis greater than 45°.

Explanation:

The question is a little confusing but, I guess the correct question should be;

You are flying a hang glider at 14 mph in the northeast direction (45°). The wind is blowing at 4 mph due north.

a) What is your airspeed?

b) What angle (direction) are you flying?

c) The wind increases to 14 mph from north. Now what is your airspeed and what direction are you flying? If your destination is to the northeast, how would you change your speed or direction so you might make it there?

NB: The difference in the question and my suggestion is highlighted boldly.

Your speed = 14 mph

direction is 45° northeast

Th wind speed = 4 mph

direction is north

We resolve the your speed and the wind speed into the horizontal and vertical components

For vertical the component component

$V_{y}$ = 14(sin 45) + 4 = 9.89 + 4 = 13.89 mph

For the horizontal speed component

$V_{x}$ = 14(cos 45) + 0 = 9.89 + 0 = 9.89 mph

Resultant speed = $\sqrt{V^{2} _{y}+V^{2} _{x} }$

==> $\sqrt{13.89^{2} +9.89^{2} }$ = 17.05 mph This is your airspeed

b) To get your direction, we use

tan ∅ = $V_{y}$ / $V_{x}$

tan ∅ = 13.89/9.89 = 1.413

∅ = $tan^{-1}$ (1.413) = 54.7° northeast direction

c) If the wind increases to 14 mph from the north, then it means the wind blows due south. As before, only the vertical component is affected .

In this case,

$V_{y}$ = 14(sin 45) - 14 = 9.89 - 14 = -4.11 mph

Resultant speed = $\sqrt{V^{2} _{y}+V^{2} _{x} }$

==> $\sqrt{4.11^{2} +9.89^{2} }$ = 10.71 mph This is your airspeed

Your direction will be,

tan ∅ = $V_{y}$ / $V_{x}$

tan ∅ = -4.11/9.89 = -0.416

∅ = $tan^{-1}$ (-0.416) = -22.58° this is the angle you'll travel relative to the east.

To head northeast, you must either increase your gliding speed or increase your angle relative to the x-axis greater than 45°.

5 0

2 years ago

7. A local sign company needs to install a new billboard. The signpost is 30 m tall, and the ladder truck is parked 24 m away fr

wolverine [178]

<h2>Solution :</h2>

Here ,

• Height of sign post = 30 m

• Distance between signpost and truck = 24 m

Let the

• Top of signpost = A

• Bottom of signpost = B

• The end of truck facing sign post be = C

Now as we can clearly imagine that the ladder will act as an hypotenuse to the Triangle ABC .

Where

• AB = Height of signpost = 30 m

• BC = distance between both = 24 m

• AC = Minimum length of ladder

→ AC² = AB² + BC² ( As we can see AB is perpendicular to BC )

→ AC² = (30)² + (24)²

→ AC² = 900 + 576

→ AC² = 1476

→ AC = 38.41875

or AC apx = 38.42

So minimum height of ladder = 38.42

6 0

2 years ago

Joel uses a claw hammer to remove a nail from a wall. He applies a force of 40 newtons on the hammer. The hammer applies a force

jarptica [38.1K]

Hi!

Mechanical advantage is defined as the ratio of force produced by an object to the force that is applied to it.

In our case, this would be the ratio of the force applied by the claw hammer on the nail to the force Joel applies to the claw hammer, which is

160:40 or 4:1

So the mechanical advantage of the hammer is four.

Hope this helps!

3 0

2 years ago

Read 2 more answers

Consider the two moving boxcars in Example 5. Car 1 has a mass of m1 = 65000 kg and a velocity of v01 = +0.80 m/s. Car 2 has a m

Amiraneli [1.4K]

Answer:

1.034m/s

Explanation:

We define the two moments to develop the problem. The first before the collision will be determined by the center of velocity mass, while the second by the momentum preservation. Our values are given by,

$m_1 = 65000kg\\v_1 = 0.8m/s\\m_2 = 92000kg\\v_2 = 1.2m/s$

Part A) We apply the center of mass for velocity in this case, the equation is given by,

$V_{cm} = \frac{m_1v_1+m_2v_2}{m_1+m_2}$

Substituting,

$V_{cm} = \frac{(65000*0.8)+(92000*1.2)}{92000+65000}$

$V_{cm} = 1.034m/s$

Part B)

For the Part B we need to apply conserving momentum equation, this formula is given by,

$m_1v_1+m_2v_2 = (m_1+m_2)v_f$

Where here $v_f$ is the velocity after the collision.

$v_f = \frac{m_1v_1+m_2v_2}{m_1+m_2}$

$v_f = \frac{(65000*0.8)+(92000*1.2)}{92000+65000}$

$v_f = 1.034m/s$

8 0

2 years ago

Determine whether each substance will sink or float in corn syrup, which has a density of 1.36 g/cm3. Write “sink” or “float” in

Tatiana [17]

Explanation:

A substance will floats if it is having lower density than the density of the liquid in which it is placed.
A substance will sink if it is having density greater than the density of the liquid in which it is kept.

Density of corn syrup = $1.36 g/cm^3$

1) Density of gasoline = $0.748 g/cm^3$

Density of the gasoline is less than the the density of corn syrup which means it will float in corn syrup.

2) Density of water = $1 g/cm^3$

Density of the water is less than the the density of corn syrup which means it will float in corn syrup.

3) Density of honey = $1.45 g/cm^3$

Density of the gasoline is more than the the density of corn syrup which means it will sink in corn syrup.

4) Density of titanium = $4.506 g/cm^3$

Density of the titanium is more than the the density of corn syrup which means it will sink in corn syrup.

3 0

2 years ago

Read 2 more answers