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gayaneshka [121]

3 years ago

7

A car accelerates at 4 m/s2 for 5 seconds. the direction of its acceleration is due east (east = positive direction). if its ini

tial velocity was 7 m/s, also due east, what is its final velocity? round your answer to the nearest meter per second.

1 answer:

Marina86 [1]3 years ago

3 0

The final velocity is 20 m/s^2

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A constant horizontal F force began to act on the initially immovable body placed on a horizontal surface. After t time the forc

mel-nik [20]

Answer:

The coefficient of friction is (F/(19.6·m)

Explanation:

The given parameters are;

The force applied to the immovable body = F

The time duration the force acts = t

The time the body spends in motion = 3·t

The acceleration due to gravity, g = 9.8 m/s²

From Newton's second law of motion, we have;

The impulse of the force = F × t = m × Δv₁

Where;

Δv₁ = v₁ - 0 = v₁

The impulse applied by the force of friction, $F_f$ is $F_f$ × (3·t - t) = $F_f$ × (2·t)

Given that the motion of the object is stopped by the frictional force, we have;

The impulse due to the frictional force = Momentum change = m × Δv₂ = $F_f$ × (2·t)

Where;

Δv₂ = v₂ - 0 = v₂

Given that the velocity, v₂, at the start of the deceleration = The velocity at the point the force ceased to act, v₁, we have;

m × Δv₂ = $F_f$ × (2·t) = m × Δv₁ = F × t

∴ $F_f$ × (2·t) = F × t

$F_f$ = F × t/(2·t) = F/2

The coefficient of dynamic friction, $\mu _k$ = Frictional force/(The weight of the body) = (F/2)/(9.8 × m)

$\mu _k$ = (F/(19.6·m)

The coefficient of friction, $\mu _k$ = (F/(19.6·m)

5 0

3 years ago

An accelerating voltage of 2.47 x 10^3 V is applied to an electron gun, producing a beam of electrons originally traveling horiz

Dmitry [639]

Answer:

6.3445×10⁻¹⁶ m

Explanation:

E = Accelerating voltage = 2.47×10³ V

m = Mass of electron

Distance electron travels = 33.5 cm = 0.335 cm

$E=\frac{mv^2}{2}\\\Rightarrow v=\sqrt{\frac{2E}{m}}\\\Rightarrow v=\sqrt{\frac{2\times 2470\times 1.6\times 10^{-19}}{9.11\times 10^{-31}}}\\\Rightarrow v=29455356.08671\ m/s$

Deflection by Earth's Gravity

$\Delta =\frac {gt^2}{2}$

Now, Time = Distance/Velocity

$\Delta =\frac {g\frac{s^2}{v^2}}{2}\\\Rightarrow \Delta =\frac{9.81\frac{0.335^2}{29455356.08671^2}}{2}\\\Rightarrow \Delta =6.3445\times 10^{-16}\ m$

∴ Magnitude of the deflection on the screen caused by the Earth's gravitational field is 6.3445×10⁻¹⁶ m

3 0

3 years ago

When we double the distance between a source of light and the

FinnZ [79.3K]

When we double the distance between a source of light and the

surface on which it falls, the amount of illumination on the surface

decreases to <em>one fourth (1/4, 0.25))</em> of the original illumination.

7 0

4 years ago

Problem 10.64 the maximum energy a bone can absorb without breaking is surprisingly small. for a healthy human of mass 67 kg , e

kvasek [131]

Answer: h = 0.30 m

Explanation:

A person jumping from height h would possess potential energy = m g h

which will convert completely into kinetic energy as person hits the ground. Now, the maximum energy absorbed by the person can be = 200 J

m = 67 kg

g = 9.8 m/s²

⇒ m g h = 200 J

⇒ h = 200 J / (67 kg × 9.8 m/s²) = 0.30 m

Hence, a person can land safely on both legs without breaking them from a height of 0.30 m only.

8 0

3 years ago

If an astronaut goes on a space walk outside the Space Station, she will quickly float away from the station unless she has a te

Strike441 [17]

Answer:

d. This statement is false. She and the Space Station share the same orbit and will stay together unless they are pushed apart.

Explanation:

In astronomy, orbit is simply a path of an object around another object in a space. That is, orbit is a path of a body that revolves around a gravitating center of mass. Examples of an orbit is are satellite around a planet, orbit around a center of galaxy, planet around the sun, and among others.

On the other hand, space station refers to a spacecraft that can support a group of human for long time in the orbit. Another names for space stations are orbital space station and orbital station.

Therefore, an astronaut goes on a space walk outside the Space Station shares the same orbit with the space station and they will stay together unless they are pushed apart.

4 0

3 years ago