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2 years ago

A car is travelling at 20m/s, accelerates at 4m/s2 . Calculate its velocity after 5s?

Physics

1 answer:

IgorLugansk [536]2 years ago

5 0

Answer:

Explanation:

The final velocity of an object that experiences a period of acceleration is given by:

v - vi = A*t

Initial velocity, vi, is = 20m/s

Acceleration, A, is 4m/2^2

Time, t, is 5 seconds

v - vi = A*t

v - 20m/s = (4m/2^2)/(5 sec)

v = (20 m/s) + (20 m/s)

v = 40 m/s

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Starting from rest, a 6.79 kg block slides 2.82 m down a rough 20.7 ◦ incline. The coefficient of kinetic friction between the b

Veronika [31]

Answer:

23.52092 J

Explanation:

m = Mass of block = 6.79 kg

s = Sliding distance = 2.82 m

$\theta$ = Angle of slide = 20.7°

$\mu$ = Coefficient of kinetic friction = 0.425

g = Acceleration due to gravity = 9.8 m/s²

Work done by the force of gravity is given by

$W=mgsin\theta\\\Rightarrow W=6.79\times 9.8\times sin20.7\\\Rightarrow W=23.52092\ J$

The work done by the force of gravity is 23.52092 J

8 0

3 years ago

A 782.10 kg car is brought from 7.60 m/s to 3.61 m/s over a time period of 4.23 seconds. What is the average force the car exper

alexandr402 [8]

Answer:

–735.17 N

The negative sign indicate that the force is acting in opposition direction to the car.

Explanation:

The following data were obtained from the question:

Mass (m) of car = 782.10 kg

Initial velocity (u) = 7.60 m/s

Final velocity (v) = 3.61 m/s

Time (t) = 4.23 s

Force (F) =?

Next, we shall determine the acceleration of the car. This can be obtained as follow:

Initial velocity (u) = 7.60 m/s

Final velocity (v) = 3.61 m/s

Time (t) = 4.23 s

Acceleration (a) =?

a = (v – u) / t

a = (3.61 – 7.60) / 4.23

a = –3.99 / 4.23

a = –0.94 m/s²

Finally, we shall determine the force experienced by the car as shown below:

Mass (m) of car = 782.10 kg

Acceleration (a) = –0.94 m/s²

Force (F) =?

F = ma

F = 782.10 × –0.94

F = –735.17 N

The negative sign indicate that the force is acting in opposition direction to the car.

4 0

3 years ago

Identify the following terms:

anastassius [24]

Answer:

atom -
the smallest particle of a chemical element that can exist.

atomic mass-
the quantity of matter contained in an atom of an element

atomic weight -
ratio of the average mass of a chemical element's atoms to some standard

protons-
stable subatomic particle that has a positive charge equal in magnitude to a unit of electron charge and a rest mass of 1.67262 × 10−27 kg

electrons-
a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids

neutrons-
a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.

energy levels-
one of the stable states of constant energy that may be assumed by a physical system
[used especially of the quantum states of electrons in atoms and of nuclei. — called also energy state.]

Covalent bonds

the interatomic linkage that results from the sharing of an electron pair between two atoms.

ionic bonds
type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound.

Valence electrons
a single electron or one of two or more electrons in the outer shell of an atom that is responsible for the chemical properties of the atom.

Lewis Dot Diagram
A way of representing atoms or molecules by showing electrons as dots surrounding the element symbol. One bond is represented as two electrons.

4 0

2 years ago

A seesaw is 4.0m long with a pivot at its midpoint. A boy who weighs 400N sits at a distance of 1.5m from the pivot. His sister

bezimeni [28]

Answer:

the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

Explanation:

Given;

length of the seesaw, L = 4.0 m

weight of the boy, W₁ = 400 N

position of the boy from the pivot, d₁ = 1.5 m

weight of her sister, W₂ = 300 N

First, make a sketch of this information given;

0---0.5m---------------------Δ--------------------------4m

↓<--------1.5m-------> <---------x--------->↓

400 N 300N

Apply the principle of moment about the pivot, to determine the value of x;

Sum of anticlockwise moment = sum of clockwise moment

400(1.5) = 300(x)

600 = 300x

x = 600/300

x = 2 cm

Thus, the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

8 0

3 years ago

An astronaut, of total mass 86.0 kg including her suit, stands on a spherical satellite of mass 360 kg, both at rest relative a

Afina-wow [57]

Answer: 0.56 m/s

Explanation:

Hi, to answer this question we have to apply the formula of the conservation of momentum.

m1 v1 = m2 v2 (because the system is stationary at the beginning)

Where:

m1 = mass of the astronaut

v1= velocity of the astronaut

m2= mass of the satellite

v2= velocity of the satellite

Replacing with the values given and solving:

86 kg (2.35m/s) = 360 kg v2

202.1 kgm/s=360kg v2

202.1kgm/s /360kg =v2

v2 = 0.56 m/s

Feel free to ask for more if needed or if you did not understand something.

5 0

3 years ago