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3 years ago

An object moves in a straight line and is speeding up. Which one of the following statements is true?

1 answer:

3 0

I could be wrong on this one, but I think the answer is the first option, The net force on the object is in the direction of motion.

Friction can be acting on the object, but if the other force(s) that are acting on the object are greater, I think the object will still be able to accelerate.

The third option can't be true, according to Newton's second law $(f=ma)$ . If there were no forces acting on the object, or if the net forces cancelled each other out, the object wouldn't be accelerating unless its mass was changing.

I suppose the last option is also technically true, but the first is more specific..?

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Which activity is the best example of cardiovascular and strength training exercises work together

Nataly [62]

it got to be jumping jacks that all i got

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3 years ago

Read 2 more answers

A 0.4000 kg sample of methanol at 16.0ºC is mixed with 0.4000 kg of water at 85.0ºC. Assuming no heat loss to the surroundings,

AVprozaik [17]

Answer:

T_finalmix = 59.5 [°C].

Explanation:

In order to solve this problem, a thermal balance must be performed, where the heat is transferred from water to methanol, at the end the temperature of the water and methanol must be equal once the thermal balance is achieved.

$Q_{water}=Q_{methanol}$

where:

$Q_{water}=m_{water}*Cp_{water}*(T_{waterinitial}-T_{final})$

mwater = mass of the water = 0.4 [kg]

Cp_water = specific heat of the water = 4180 [J/kg*°C]

T_waterinitial = initial temperature of the water = 85 [°C]

T_finalmix = final temperature of the mix [°C]

$Q_{methanol}=m_{methanol}*Cp_{methanol}*(T_{final}-T_{initialmethanol})$

Now replacing:

$0.4*4180*(85-T_{final})=0.4*2450*(T_{final}-16)\\142120-1672*T_{final}=980*T_{final}-15680\\157800=2652*T_{final}\\T_{final}=59.5[C]$

4 0

3 years ago

Suppose we have two planets with the same mass, but the radius of the second one is twice the size of the first one. How does th

bogdanovich [222]

The free-fall acceleration on the second planet is one-fourth the value of the first planet.

Calculation:

Consider the mass of planet A to be, M

the mass of planet B to be, Mₓ = M

the radius of planet A to be, R₁

the radius of planet B to be, R₂

The acceleration due to gravity on planet A's surface is given as:

g = GM/R₁² - (1)

Similarly, the acceleration due to gravity on planet B's surface is given as:

g' = GM/R₂² [where, R₂ = 2R₁]

= GM/4R₁² -(2)

From equation 1 & 2, we get:

g/g' = GM/R₁² ÷ GM/4R₁²

g/g' = 4/1

Thus we get,

g' = 1/4 g

Therefore, the free-fall acceleration on the second planet is one-fourth the value of the first planet.

Learn more about free-fall here:

<u>brainly.com/question/13299152</u>

#SPJ4

6 0

2 years ago

Two pucks collide with each other. after the collision they do not stick together. is kinetic energy conserved in the collision?

miv72 [106K]

Since they do not stick after collision hence collision is elastic. In elastic collision, both momentum and kinetic energy is conserved because in this type of collision, first body deforms but then quickly regains its former shape and transfers its kinetic energy to the second pluck.
So kinetic energy is conserved.

5 0

3 years ago

Which of the following are possible causes of mass extinctions that scientists have identified

Alecsey [184]

Answer:

over harvesting, pollution, introduction of invasive species such as new predators and food competitors

Explanation:

The main cause of mass extinction is Humans cause extinction of a species through overharvesting. The second main cause is pollution ., introduction of invasive species such as new predators and food competitors, habitat destruction, overhunting and other influences. Another very important cause of mass extinction is the unsustainable human population growth.

The five mass extinction events are

Ordovician Mass Extinction

Devonian Mass Extinction

Permian Mass Extinction

Triassic -Jurassic Mass Extinction

and Cretaceous -Tertiary (or the K-T) Mass Extinction.

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4 years ago