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3 years ago

What is the speed of an object that travels 20 meters in 4 seconds?

Physics

1 answer:

Iteru [2.4K]3 years ago

5 0

Given:-

Distance covered by the particle (s) = 20 m
Time taken (t) = 4 seconds

To Find: Speed of it.

We know,

v = s/t

where,

v = Speed,
s = Distance &
t = Time taken.

Putting the values,

v = (20 m)/(4 s)

→ v = 5 m/s (Ans.)

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Can it is possible to complete half syllabus of physics class 11 in 8 days?

castortr0y [4]

Answer:

In the human thoughts, there is possible and impossible. In God's world everything is possible. If you keep thinking this you'll never start to study. Just get up, open the book and start to study like you do. Believe in yourself!

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3 years ago

A block of mass m=16.8 kg is sliding on a surface with initial velocity v=23.2 m/s. The block has a coefficient of kinetic frict

Firdavs [7]

Answer:

t = 23.92 s

Explanation:

Newton's second law:

∑F = m*a Formula (1)

∑F : algebraic sum of the forces in Newton (N)

m : mass s (kg)

a : acceleration (m/s²)

We define the x-axis in the direction parallel to the movement of the block and the y-axis in the direction perpendicular to it.

Forces acting on the block

W: Weight of the block : In vertical direction, downward

FN : Normal force : perpendicular to the floor, upward

fk : Kinetic friction force: parallel to the floor and opposite to the movement

F = 86.4 N , in the direction of the motion

Calculated of the W

W= m*g

W= 16.8 kg* 9.8 m/s² = 164.64 N

Calculated of the FN

We apply the formula (1)

∑Fy = m*ay ay = 0

FN - W = 0

FN = W

FN = 164.64 N

Calculated of the fk

fk = μk*FN

fk = 0.426* 164.64 N

fk = 70.13 N

We apply the formula (1) to calculated acceleration of the block:

∑Fx = m*ax , ax= a : acceleration of the block

F - fk = m*a

86.4 -70.13 = (16.8)*(-a)

16.26 = (16.8)*(-a)

a = -(16.26 )/ (16.8)

a = - 0.97 m/s²

Kinematics of the block

Because the block moves with uniformly accelerated movement we apply the following formula :

vf = v₀ + a*t Formula (2)

Where:

t: time interval (m)

v₀: initial speed (m/s)

vf: final speed (m/s)

Data:

v₀ = 23.2 m/s

vf = 0

a = -0.97 m/s²

Time it takes for the block to stop

We replace data in the formula (2) to calculate the time

vf= v₀+a*t

0 = 23.2+( -0.97)*t

(0.97)*t = 23.2

t = 23.2 / (0.97)

t = 23.92 s

7 0

3 years ago

It is known that the gravitational force of attraction between two alpha particles is much weaker than the electrical repulsion.

natali 33 [55]

Answer:

The ratio of gravitational force to electrical force is 3.19 x 10^-36

Explanation:

mass of an alpha particle = 6.64 x $10^{-27}$ kg

charge on an alpha particle = +2e = +2(1.6 x $10^{-19}$ C) = 3.2 x $10^{-19}$ C

distance between particles = d

For gravitational attraction:

The force of gravitational attraction F = $\frac{Gm^{2} }{r^{2} }$

where G = gravitational constant = 6.67 x $10^{-11}$ m^3 kg^-1 s^-2

r = the distance between the particles = d

m = the mass of each particle

therefore, gravitational force = $\frac{6.67*10^{-11}*(6.64*10^{-27} )^{2} }{d^{2} }$ = $\frac{2.94*10^{-63} }{d^{2} }$ Newton

For electrical repulsion:

Electrical force between the particles = $\frac{-kQ^{2} }{r^{2} }$

where k is the Coulomb's constant = 9.0 x $10^{9}$ N•m^2/C^2

r = distance between the particles = d

Q = charge on each particle

therefore, electrical force = $\frac{-9*10^{9}*(3.2*10^{-19} )^{2} }{d^{2} }$ = $\frac{-9.216*10^{-28} }{d^{2} }$ Newton

the negative sign implies that there is a repulsion on the particles due to their like charges.

Ratio of the magnitude of gravitation to electrical force = $\frac{2.94*10^{-63} }{9.216*10^{-28} }$

==> 3.19 x 10^-36

8 0

3 years ago

What affects a material’s resistance?

Keith_Richards [23]

Many things can affect a material's resistance, The type of material, how the material is being held (If its laying flat, being pulled, etc). What the material is used for, and how much material there is. Hope this helps!

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3 years ago

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Which statement best describes a wave?

dedylja [7]

Correct answer choice is:

D. A continuous transmission of energy from one location to the next.

Explanation:

Waves include the carrier of energy without the carrier of matter. In outcome, a wave can be characterized as a change that progresses into a medium, carrying energy from one spot (its source) to different spot without carrying matter.

3 0

3 years ago

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