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xz_007 [3.2K]
3 years ago
12

Find the work done by a force of 8 pounds acting in the direction of 44° to the horizontal in moving an object 7 feet from (0, 0

) to (7, 0). Round answer to the nearest tenth of a foot-pound.
Physics
1 answer:
iris [78.8K]3 years ago
8 0

Answer:

40.3 ft-lbs

Explanation:

Work = Force•Distance = (Force)(Distance)(cosΘ)

Note what you know and/or don't know. In this case:

Force = 8lbs

Distance = 7ft

Θ = 44°

So with that and the formula of work above, we can say:

Work = (8lbs)(7ft)(cos44°) = 40.28...ft-lbs

When rounded you have 40.3 ft-lbs of work done by the force.

Side note: Just to be clear, the formula Force•Distance is said as Force "dot" Distance. It's a dot product and not just a multiplication sign; which is why the angle is important to know.

Force×Distance is said as Force "cross" Distance, which relates to a different kind of force and has a slightly different formula.

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Sidana [21]
The area-

The area under the line in a velocity-time graph represents the distance travelled. To find the distance travelled in the graph above, we need to find the area of the light-blue triangle and the dark-blue rectangle.

<span><span>Area of light-blue triangle -
<span>The width of the triangle is 4 seconds and the height is 8 meters per second. To find the area, you use the equation: <span>area of triangle = 1⁄2 × base × height </span><span>so the area of the light-blue triangle is 1⁄2 × 8 × 4 = 16m. </span></span></span><span> Area of dark-blue rectangle The width of the rectangle is 6 seconds and the height is 8 meters per second. So the area is 8 × 6 = 48m.</span><span> Area under the whole graph <span>The area of the light-blue triangle plus the area of the dark-blue rectangle is:16 + 48 = 64m.<span>This is the total area under the distance-time graph. This area represents the distance covered.</span></span></span></span>
7 0
3 years ago
(1 point) A projectile is fired from ground level with an initial speed of 600 m/sec and an angle of elevation of 30 degrees. Us
konstantin123 [22]

Answer:

(a) The range of the projectile is 31,813.18 m

(b) The maximum height of the projectile is 4,591.84 m

(c) The speed with which the projectile hits the ground is 670.82 m/s.

Explanation:

Given;

initial speed of the projectile, u = 600 m/s

angle of projection, θ = 30⁰

acceleration due to gravity, g = 9.8 m/s²

(a) The range of the projectile in meters;

R = \frac{u^2sin \ 2\theta}{g} \\\\R = \frac{600^2 sin(2\times 30^0)}{9.8} \\\\R = \frac{600^2 sin (60^0)}{9.8} \\\\R = 31,813.18 \ m

(b) The maximum height of the projectile in meters;

H = \frac{u^2 sin^2\theta}{2g} \\\\H = \frac{600^2 (sin \ 30)^2}{2\times 9.8} \\\\H = \frac{600^2 (0.5)^2}{19.6} \\\\H = 4,591.84 \ m

(c) The speed with which the projectile hits the ground is;

v^2 = u^2 + 2gh\\\\v^2 = 600^2 + (2 \times 9.8)(4,591.84)\\\\v^2 = 360,000 + 90,000.064\\\\v = \sqrt{450,000.064} \\\\v = 670.82 \ m/s

5 0
3 years ago
A baseball player leads off the game and hits a long home run. The ball leaves the bat at an angle of 70.0 from the horizontal w
professor190 [17]

Answer: 211.059 m

Explanation:

We have the following data:

\theta=70\° The angle at which the ball leaves the bat

V_{o}=55 m/s The initial velocity of the ball

g=-9.8 m/s^{2} The acceleration due gravity

We need to find how far (horizontally) the ball travels in the air: x

Firstly we need to know this velocity has two components:

<u>Horizontally:</u>

V_{ox}=V_{o}cos \theta (1)

V_{ox}=55 m/s cos(70\°)=18.811 m/s (2)

<u>Vertically:</u>

V_{oy}=V_{o}sin \theta (3)

V_{oy}=55 m/s sin(70\°)=51.683 m/s (4)

On the other hand, when we talk about parabolic movement (as in this situation) the ball reaches its maximum height just in the middle of this parabola, when V=0 and the time t is half the time it takes the complete parabolic path.

So, if we use the following equation, we will find t:

V=V_{o}+gt=0 (5)

Isolating t:

t=\frac{-V_{o}}{g} (6)

t=\frac{-55 m/s}{-9.8 m/s^{2}} (7)

t=5.61 s (8)

Now that we have the time it takes to the ball to travel half of is path, we can find the total time T it takes the complete parabolic path, which is twice t:

T=2t=2(5.61 s)=11.22 s (9)

With this result in mind, we can finally calculate how far the ball travels in the air:

x=V_{ox}T (10)

Substituting (2) and (9) in (10):

x=(18.811 m/s)(11.22 s) (11)

Finally:

x=211.059 m

8 0
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Gnesinka [82]
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3 years ago
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DiKsa [7]

Answer:

B

Explanation:

Because vector Y is longer than vector X

so when you take a magnitude( without minus ) each other

you see that Y>X

8 0
3 years ago
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