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Gwar [14]
3 years ago
14

Which of the following best demonstrates the effect of static friction? A. A person dropping a ball to the ground. B. A person p

ushing a couch and it slowly sliding across a floor C. A person pushing a couch without being able to move it D. A person moving a ball through a stream of water
Physics
1 answer:
Dominik [7]3 years ago
6 0

Answer:

C.

Explanation:

A person pushing a couch will face resistive force of friction . When resistive force is greater then his force of effort , couch will not move. This force is static friction because the couch is stationary. When the force of effort is increased , magnitude of static friction also increases keeping the couch stationary. The ability of the static friction to increase its magnitude is limited by a maximum value beyond which the couch starts moving. The static friction is then converted into kinetic friction.

In rest of the three cases object is already moving so kinetic friction is in action.

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Shante makes a diagram to compare the effects of short-term and long-term environmental changes. Which statement should she plac
irinina [24]
Answer: affect organisms
hope this helps you out .
5 0
3 years ago
An electric motor draws out 5 A of current from a 20 V battery. How much power is it using?
irinina [24]

Answer:

Explanation:

P = VI = 20(5) = 100 W

7 0
3 years ago
Read 2 more answers
A man takes 20 seconds to climb 5m up a ladder. He weighs 720N. Calculate the power he must deliver to do this.
Inessa05 [86]

Answer:

180 W

Explanation:

The work done by the man against gravity is equal to its gain in gravitational potential energy:

W=mg\Delta h

where

(mg) = 720 N is the weight of the man

\Delta h= 5 m is the change in height

Substituting,

W=(720)(5)=3600 J

The power he must deliver is given by

P=\frac{W}{t}

where

W = 3600 J

t = 20 s is the time taken

Substituting,

P=\frac{3600}{20}=180 W

3 0
3 years ago
You are driving at the speed of 27.7 m/s (61.9764 mph) when suddenly the car in front of you (previously traveling at the same s
densk [106]

Here when car in front of us applied brakes then it is slowing down due to frictional force on it

So here we can say that friction force on the car front of our car is given as

F_f = \mu m g

So the acceleration of car due to friction is given as

F_{net} = - \mu mg

a = \frac{F_{net}}{m}

a = -\mu g

now it is given that

\mu = 0.868

g = 9.81 m/s^2

so here we have

a = -0.868 * 9.81

a = -8.52 m/s^2

so the car will accelerate due to brakes by a = - 8.52 m/s^2

4 0
3 years ago
What do you think we call this graphical representation based on your prior experience with electric fields and electric field l
slavikrds [6]

Answer:

Explanation:

The strengthcompassion field is proportional to the closeness of the field lines—more precisely, it is proportional to the number of lines per unit area perpendicular to the lines. The direction of the electric field is tangent to the field line at any point in space. Field lines can never cross. These pattern of lines, sometimes referred to as electric field lines, point in the direction that a positive test charge would accelerate if placed upon the line. As such, the lines are directed away from positively charged source charges and toward negatively charged source charges.

Rules for drawing electric field lines

1. Electric field lines are always drawn from High potential to

low potential.

2. Two electric field lines can never intersect each other.

3. The net electric field inside a Conductor is Zero.

4. Electric field line from a positive charge is drawn radially outwards and from a negative charge radially inwards.

5. The density of electric field lines tells the strength of the electric field at that region.

6. Electric field lines terminate Perpendicularly to the surface of a conductor.

A vector quantity has a direction and a magnitude, while a scalar has only a magnitude. You can tell if a quantity is a vector by whether or not it has a direction associated with it.

So, electric fields are vector quantity due to the fact any student can tell you that a compass is used to determine which direction is north.

Since the compass always point northward, then it has a direction and magnitude and so it is a vector quantity

6 0
3 years ago
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