1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
umka2103 [35]
3 years ago
15

A running back holds 0.25 kg football and runs 100m down the football field. In addition to scoring six points for his team, he

also does ___ work on the football
A) no
B) 25 J of
C) 100 J of
D) 250 J of

Select the option which will cause a worker to do the maximum amount of work.
A) Using a lever to lift 100 newtons up to 4 meters on to a shelf
B) Using her hands to lift 200 newtons up 1 meter on to a table
C)Using a ramp to lift a 200 newton box up 1 meter into a truck
D) Using a pulley to lift to 100 newton box up 3 meters onto a platform

The power resulting from 420 Nm of work being completes in 3 seconds
A) 140 Joules
B)140 Newton-meters

What do you know about the law of conservation of energy? Check all the statements that are true

A)The total amount of mass in a system remains constant regardless of the changes that take place in system
B) Energy is neither creates or destroyed, it only changes form
C) Half-way down the ramp, PE = 50J and KE = 50J
D) In a closed system, a system that isolated from its surrounds, the total energy of the system is conserved
Physics
1 answer:
katrin2010 [14]3 years ago
5 0

Answer:

<h2>1) there is no work done on the system</h2><h2>2) A) Using a lever to lift 100 newtons up to 4 meters on to a shelf</h2><h2 /><h2>3) P = 140 W</h2><h2>4) D) In a closed system, a system that isolated from its surrounds, the total energy of the system is conserved</h2>

Explanation:

1) As we know that work done is the product of force and the displacement of the point of action where force is applied

So here we have

W = 0

as there is no displacement in the direction where the force is applied

2)As we know that work is product of force and displacement

So we will have

W_1 = 100 \times 4 = 400 J

W_2 = 200 \times 1 = 200 J

W_1 = 200 \times 1 = 200 J

W_1 = 100 \times 3 = 300 J

So maximum work is done on

A) Using a lever to lift 100 newtons up to 4 meters on to a shelf

3)

As we know that power is rate of work done

so we have

P = \frac{W}{t}

P = \frac{420}{3}

P = 140 W

4)

As per energy conservation we know that

D) In a closed system, a system that isolated from its surrounds, the total energy of the system is conserved

You might be interested in
Which of the following illustrates two resistors in a parallel circuit
IRINA_888 [86]

In option A there are two resistors in which two terminals of resistors are connected with the terminals of battery so here they are connected in parallel.

In option B all resistors and battery is connected in a single loop so it is a series combination of all.

In option C all three resistors are connected by their terminals to a single battery so here all three resistor are in parallel with the battery.

In option D only one resistor is connected in series with a battery as one single loop is there.

So in the above all cases two resistors are in parallel with battery in option A

8 0
3 years ago
Read 2 more answers
A sailboat is traveling across the ocean with a speed of 4 m/s when large gusts of wind pick up that starts to accelerate the sa
MatroZZZ [7]
Initial velocity, u = 4 m/s

acceleration due to gusts of wind = 3 m/s^2

time, t = 1 min = 60 s

Let distance travelled = S

From equation of motion,

S = ut +  \frac{1}{2} a {t}^{2}  \\  \\ S = 4 \times 60 +   \frac{1}{2}  \times 3 \times  {60}^{2}  \\  \\ S = 240 + 5400 \\  \\ S = 5640 \: m

Thus, the boat would have traveled 5640m after gusts picked up.
4 0
3 years ago
Read 2 more answers
Which image represents the force on a positively charged particle caused by an approaching magnet?
Amanda [17]

Answer:

Image B represents the force on a positively charged particle caused by an approaching magnet.

Explanation:

The most fundamental law of magnetism is that like shafts repulse each other and dissimilar to posts pull in one another; this can without much of a stretch be seen by endeavoring to put like posts of two magnets together. Further attractive impacts additionally exist. On the off chance that a bar magnet is cut into two pieces, the pieces become singular magnets with inverse shafts. Also, pounding, warming or winding of the magnets can demagnetize them, on the grounds that such dealing with separates the direct game plan of the particles. A last law of magnetism alludes to maintenance; a long bar magnet will hold its magnetism longer than a short bar magnet. The domain theory of magnetism expresses that every single enormous magnet involve littler attractive districts, or domains. The attractive character of domains originates from the nearness of significantly littler units, called dipoles. Iotas are masterminded in such a manner in many materials that the attractive direction of one electron counteracts the direction of another; in any case, ferromagnetic substances, for example, iron are unique. The nuclear cosmetics of these substances is with the end goal that littler gatherings of particles unite as one into zones called domains; in these, all the electrons have the equivalent attractive direction.

4 0
3 years ago
If the temperature of water warming on a hot plate rises 10 degrees Celsius [°C], what is the change in temperature in units of
Luba_88 [7]

Answer:

Delta_temp = 18[°F]

Explanation:

°F = 9/5*(10)

°F = 18

Note: It is important to clarify that it is only a temperature increase, that it is only a temperature increase. The question is not related to converting from 10°C to fahrenheit degrees

4 0
3 years ago
A string is wrapped around a pulley with a radius of 2.0 cm. The pulley is initially at rest. A constant force of 50 N is applie
Ray Of Light [21]

Answer:

0.20kg-m^2

Explanation:

Let the linear velocity of the rope(=of pulley) is v m/s

Using kinematic equation

=> v = u + at

=>v = 0 + 4.9a

=>v = 4.9a ------------ eq1

By v^2 = u^2 + 2as

=>v^2 = 0 + 2 x v/4.9 x 1.2

=>4.9v^2 - 2.4v = 0

=>v(4.9v - 2.4) = 0

=>v = 2.4/4.9 = 0.49 m/s

Thus by v = r x omega

=>omega = v/r = 0.49/0.02 = 24.49 rad/sec

BY W = F x s = 50 x 1.2 = 60 J

=>KE(rotational) = W = 1/2 x I x omega^2

=>60 = 1/2 x I x (24.49)^2

=>I = 0.20 kg-m^2

5 0
3 years ago
Other questions:
  • A mass is oscillating horizontally on a spring. At the locations A, B, C, D, and E, photogates are used to measure the speed of
    7·1 answer
  • The voltage across a parallel-plate capacitor with area A = 820 cm2 and separation d = 5 mm varies sinusoidally as V = (14 mV)co
    8·1 answer
  • PLEASE HELP!!!
    12·2 answers
  • PLEASE HELP Which landforms can be associated with the three types of plate boundaries?
    7·1 answer
  • What forms when two continental plates collide?
    12·1 answer
  • The food calorie, equal to 4186 J, is a measure of how much energy is released when food is metabolized by the body. A certain b
    6·1 answer
  • How to work out Initial volume Boyle’s law
    11·1 answer
  • Explain how an object can have force acting on it but not be acceleration?
    5·1 answer
  • А
    5·2 answers
  • How did black holes get their name
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!