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3 years ago

When you lift a book of the ground to your desk, what kind of work do you do, negative or positive?

1 answer:

8 0

It would be kinetic energy. Let's say the book is weighs 10 Newtons you need to use a force of 10 Newtons to lift the book. In other words it's positive. As you move the book you're giving it energy. Namely potential energy which will turn to kinetic energy if you let it go. So you're changing it's position and energy.

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What statement best describes what it means to maximize your efforts in sports?

Yuliya22 [10]

What statement best describes what it means to maximize your efforts in sports?

D.none of the above

5 0

2 years ago

James has a mass of 98 kg and Basma has a mass of 59 kg. James is running at 3.0 m/s, while Basma is running at 4.0 m/s.

belka [17]

a. The most momentum is attained by James.

b. The resultant force acting on her is 90.77N.

c. Time taken for him to stop is 3.24 s

<h3>What is momentum?</h3>

Momentum of any object is the product of the velocity of the object and its mass.

P =mv

James has a mass of 98 kg and Basma has a mass of 59 kg. James is running at 3.0 m/s, while Basma is running at 4.0 m/s.

Substitute the values, we get

P jane= 98 kg x 3

P jane= 294 kg.m/s

Momentum of Basma, is

P Basma = 59 kg x 4

P Basma = 236 kg.m/s

Therefore, the momentum is large for James.

b. Basma approaches a road, so she stops quickly. It takes her 2.6 seconds to stop. The resultant force acting on her

F. t = P Basma

F =[ 236/2.6

F = 90.77 N

Thus, the resultant force on Basma is 90.77 N.

c. James also stops for the road. If he were to have the same resultant force acting on him, Time taken for him to stop is

F = 90.77 = P james/t

t = 294 / 90.77

t = 3.24 s

Thus, time taken for James to stop for the same resultant force is 3.24 s

Learn more about momentum.

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5 0

1 year ago

A motor with an operating resistance of 32 ohms is connected to a voltage source. the current in the circuit is 3.8

Phantasy [73]

V = I · R = (3.8 Amperes) · (32 ohms) = 121.6 volts

5 0

3 years ago

A 28 kg mass suspends from a light rope 18 m long & is held to one side by the horizontal force, F, as shown below.

frutty [35]

Answer: 215.15 N

Explanation:

If we draw a free body diagram of the mass we will have the following:

$\sum{F_{x}}=-Tcos\theta + F=0$ (1)

$\sum{F_{y}}=Tsin\theta - mg=0$ (2)

Where $T$ is the tension force of the rope, $m=28 kg$ the mass, $g=9.8 m/s^{2}$ the acceleration due gravity and $mg$ is the weight.

On the other hand, we can calculate $\theta$ as follows:

$cos\theta=\frac{s}{l}$

$\theta=cos^{-1}(\frac{s}{l})$

Where $s=11.1 m$ and $l=18 m$

$\theta=cos^{-1}(\frac{11.1 m}{18 m})$

$\theta=51.9\°$ (3)

Now, we firstly need to find $T$ from (2):

$T=\frac{mg}{sin\theta}$ (4)

$T=\frac{(28 kg)(9.8 m/s^{2})}{sin(51.9\°)}$

$T=348.69 N$ (5)

Substituting (5) in (1):

$F=Tcos\theta$ (6)

$F=348.69 N cos(51.9\°)$

Finally:

$F=215.15 N$

8 0

3 years ago

balanced rock has a mass of about 36,000 kg. if the acceleration due to gravity is 9.8 meters per second squared, what is the fo

likoan [24]

The force the rock is exerting on its pedestal is, according to the formula used to calculate force, which is Force = Mass * Acceleration, is 352,800.

4 0

2 years ago