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3 years ago

LOOK AT ATTACHMENT AND ANSWER QUESTION!

Physics

2 answers:

natima [27]3 years ago

7 0

Energy can't be destroyed.
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malfutka [58]3 years ago

6 0

T believe the answer is B

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In nuclear reaction 5 kg of reactants give 2kg of products

dlinn [17]

Choice A is correct.======Kinetic energy equation: KE = (1/2)(m)(v²)This tells us that KE is directly proportional to mass and the square of velocity. In other words, the more mass and more velocity an object has, the more kinetic energy.If an object is sitting at the top of a ramp, there is no velocity and therefore no kinetic energy. Choices B and D are wrong.A golf ball has more mass than a ping-pong ball, so a ping-pong ball would have less kinetic energy than a golf ball rolling off the end of a ramp. Choice C is wrong.Choice A is correct.

6 0

2 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:

Horizontally:

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

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

Vertically:

$V_{oy}=V_{o}sin \theta$ (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

2 years ago

Why is the perfect mechine is not possible in the real life?

Vinvika [58]

Answer:

Because the mechanical advantage of the machine is affected by friction and weight but velocity ratio is not. So, mechanical advantage is less than velocity rate. Thus, the machine's efficiency is less than 100% and can't be a perfect machine

3 0

2 years ago

A 235 kg crate is pulled across a horizontal surface with a force of 760 N applied at an

AnnyKZ [126]

Answer:

658.16N

Explanation:

Step one:

given data

mass m= 235kg

Force F= 760N

angle= 30 degrees

Required

The horizontal component of the force

Step two:

The horizontal component of the force

Fh= 760cos∅

Fh=760cos30

Fh=760*0.8660

Fh=658.16N

3 0

2 years ago

A student places her 490 g physics book on a frictionless table. She pushes the book against a spring, compressing the spring by

Paul [167]

Answer:

book speed is 3.99 m/s

Explanation:

given data

mass m = 490 g = 0.490 kg

compressing x = 7.10 cm = 0.0710 m

spring constant k = 1550 N/m

to find out

book speed

solution

we know energy is conserve so

we can say

loss in spring energy is equal to gain in kinetic energy

$\frac{1}{2}*k*x^2 = \frac{1}{2}*m*v^2$ ..................1

put here value

$\frac{1}{2}*1550*0.071^2 = \frac{1}{2}*0.490*v^2$

v = 3.99 m/s

so book speed is 3.99 m/s

5 0

3 years ago