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
sesenic [268]
3 years ago
12

a 0.4 kg block rests on a desk. the coefficient of static friction is 0.2. You push the side of the block but do not have a spri

ng scale to measure the force you use. the block does not move. which statement is true about the force of static friction?
Physics
2 answers:
ladessa [460]3 years ago
7 0
Static friction is greater than Applied force
saw5 [17]3 years ago
6 0

Answer:

D. It is no smaller than 0.78N

Explanation:

The question is incomplete. These are all the options :

A. It is no larger than 0.78N

B. It is 0.78N

C. It is 0.08N

D. It is no smaller than 0.78N

To solve this problem, we have the data of :

m=0.4kg

Where ''m'' is the mass of the block

μ = 0.2

Where ''μ'' is the coefficient of static friction

If we want to find the magnitude of the force of static friction we need to use the following equation :

F_{sf}= μ.F_{N} (I)

Where ''F_{N}'' is the normal force that the desk exerts on the block. Its magnitude is equal to the weight (because we suppose that the block rests horizontally on the desk).

The weight ''W'' can be calculated as :

W=m.g

Where ''m'' is the mass and ''g'' is the acceleration due to gravity.

The value of ''g'' is

g=9.81\frac{m}{s^{2}}

The weight of the block is

W=(0.4kg).(9.81\frac{m}{s^{2}})

W=3.924N

Now, the weight is equal to the normal force ⇒

W=F_{N}=3.924N

Using the equation (I) :

F_{sf}=(0.2).(3.924N)

F_{sf}=0.7848N

The correct option is D. It is no smaller than 0.78N

You might be interested in
A 2.00-kg object traveling east at 20.0 m/s collides with a 3.00-kg object traveling west at 10.0 m/s.
ELEN [110]
Momentum = mass x velocity

Before collision
Momentum 1 = 2 kg x 20 m /s = 40 kg x m/s
Momentum 2 = 3 kg x -10m/s = -30 kg x m/s

After collision
Momentum 1 = 2 kg x -5 m/s = -10 m/s
Momentum 2 = 3 kg x V2 = 3V2

Total momentum before = total momentum after
40 + -30 = -10 + 3V2
V2 = <span>6.67 m/s

Total kinetic energy before
</span><span>= (1/2) [ 2 kg * 20 m/s * 2 + 3 kg * ( -10 m/s) *2 ]
= 550 J
</span>
<span>Total kinetic energy after
</span>= (1/2) [ 2 kg * ( - 5 m/s) * 2 + 3 kg * 6.67 m/s *2 ]
= 91.73 J

Total kinetic energy lost during collision
=<span>550 J - 91.73 J
= 458.27 J</span>

8 0
3 years ago
Read 2 more answers
How many planets are there?
Y_Kistochka [10]

Answer:

There are eight planets in our Solar System.

Explanation:

4 0
3 years ago
Read 2 more answers
Which phrase best describes the time period in which the current body of scientific knowledge was developed? A. Just over the la
LiRa [457]

Answer:

The correct option is;

B. Throughout all of history

Explanation:

A body of knowledge comprises of a given collection of concepts, activities and terms that represents a professional discipline that is outlined by the associated scholarly society, therefore, scientific knowledge, being comprised of very diverse field of knowledge, with different approaches and  changing understanding is taking as a process of learning about the universe data collection, experimenting analysis and communication with a theme of systems, equilibrium, models and constant change which makes the basis of the body of scientific knowledge to be throughout all of history.

3 0
3 years ago
Which of the following is not an indication of a chemical reaction? a substance dissolves formation of a precipitate color chang
SVETLANKA909090 [29]

a substance dissolves.  


like adding a soluble salt to water, it just dissolves, i.e dissociates homogeneously as water is able to dissociate salts (ionic compounds) into its ions. (it can also dissociate other non-ionic compounds like HCL)  


the salt still remains chemically as a salt and is unchanged chemically thus it is not an indication of a chemical reaction as no chemical reaction has taken place.  


the formation of a precipitate is a chemical reaction because a new substance (i.e new chemical) is formed. For example adding aqueous sodium hydroxide into an aqueous solution with CU2+ cations will form a blue precipitate (that is copper (II) hydroxide which is insoluble, hence it precipitates). Since a new chemical is formed, a chemical reaction has taken place and thus indicates a chemical reaction.  


color change... im not sure but usually a color change will only occur when a new substance is formed. Like iron corrodes (i.e rust) slowly in moist air to form hydrated iron (III) oxide that is rust. (brown color).  


usually adding a mixture to a mixture has little energy change, i.e little heat taken in by the reaction mixture or little heat given out by the reaction mixture. Whereas when a new substance is formed, there is usually noticeable energy change like the container gets colder or hotter (without heat being supplied of course). For example dissolving basic oxides into water releases energy ( more energy released than gained = exothermic reaction).  


i think that should be the answer... hope it helped :D

4 0
3 years ago
Read 2 more answers
Which of the following is equal to impulse?<br> A. Ft<br> B. m/s<br> C. pt<br> D. mv
tankabanditka [31]
Answer: A (Ft)

Explanation: The impulse experienced by the object equals the change in momentum of the object. In equation form, F • t = m • Δ v
5 0
3 years ago
Other questions:
  • Choosing to run so that you can become a better runner is an example of which fitness principle?
    13·2 answers
  • A 1200-N crate rests on the floor. How much work is required to move it at constant speed (a) 5.0 m along the floor against a fr
    14·1 answer
  • Jade and her roommate Jari commute to work each morning, traveling west on I-10. One morning Jade left for work at 6:45 A.M., bu
    15·1 answer
  • If the distance from your eye's lens to the retina is shorter than for a normal eye, you will struggle to see objects that are
    13·1 answer
  • Which technology has allowed for space exploration
    11·2 answers
  • A bullet with a mass of 0.040 kg collides inelastically with a wooden block of mass 1.5 kg, initially at rest. After the collisi
    14·1 answer
  • Can y’all please help me with the two part question?
    6·1 answer
  • To cut down on injuries, a highway guardrail is designed to be moved a maximum of 0.05 meters when struck by a car. What is the
    12·1 answer
  • Investigating arson can be a very complicated and complex job, as you learned in the unit! It is also generally a time sensitive
    15·1 answer
  • Please urgent science question explaining needed
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!