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3 years ago

What is the change in velocity of a 22-kg object that experiences a force of 15 N for

Physics

1 answer:

vagabundo [1.1K]3 years ago

3 0

Answer:

Force = mass × acceleration

Acceleration:

${ \tt{15 = (22 \times a)}} \\ { \tt{a = \frac{15}{22} \: {ms}^{ - 2} }}$

From first Newton's equation of motion:

${ \bf{v = u + at}}$

Change = v - u:

${ \tt{v - u = (a \times t)}} \\ { \tt{v - u = ( \frac{15}{22} \times 1.2) }} \\ { \tt{v - u = 0.82 \: {ms}^{ - 2} }}$

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A child\'s top is held in place, upright on a frictionless surface. The axle has a radius of r = 2.96 mm. Two strings are wrappe

sladkih [1.3K]

Answer:

Explanation:

Given

radius r=2.96 mm

Tension T=2.4 N

time taken=0.74 s

Let $\alpha$ be the angular acceleration

$2 T\times r=I\times \alpha$

$2\times 2.4\times 2.96\times 10^{-3}=0.5\times m\times (2.96\times 10^{-3})^2\times \alpha$

$\alpha =\frac{4\times 2.4}{m\times 2.96\times 10^{-3}}$

$\alpha =\frac{3.24\times 10^3}{m} rad/s^2$

$\omega =\omega _0+\alpha \cdot t$

$\omega =0+\frac{3.24\times 10^3}{m}\times 0.74$

$\omega =\frac{2.4\times 10^3}{m} rad/s$

Angular momentum

$L=I\omega$

$L=0.5\times mr^2\times \omega$

$L=0.5\times m\times (2.96\times 10^{-3})^2\times \frac{2.4\times 10^3}{m}$

$L=0.01051 kg-m^2/s$

4 0

2 years ago

You set a tuning fork into vibration at a frequency of 723 Hz and then drop it off the roof of the Physics building where the ac

zaharov [31]

Answer:

Explanation:

Given

Original Frequency $f=723\ Hz$

apparent Frequency $f'=697\ Hz$

There is change in frequency whenever source move relative to the observer.

From Doppler effect we can write as

$f'=f\cdot \frac{v-v_o}{v+v_s}$

where

$f'=$ apparent frequency

v=velocity of sound in the given media

$v_s=$ velocity of source

$v_0=$ velocity of observer

here $v_0=0$

$697=723\cdot (\frac{343-0}{343+v_s})$

$v_s=(\frac{f}{f'}-1)v$

$v_s=(\frac{723}{697}-1)\cdot 343$

$v_s=12.79\approx 12.8\ m/s$

i.e.fork acquired a velocity of $12.8 m/s$

distance traveled by fork is given by

$v^2-u^2=2as$

where v=final velocity

u=initial velocity

a=acceleration

s=displacement

$v_s^2-0=2\times 9.8\times s$

$s=\frac{12.8^2}{2\times 9.8}$

$s=8.35\ m$

5 0

3 years ago

Pls pls pls pls help!!!!!

Natasha2012 [34]

Answer:

The net upward force the man experiences is approximately 1,324.8 N

The net downward force the man experienced is approximately 556.8 N

Explanation:

The given mass of the man, m = 96 kg

The acceleration of the elevator, a = 4.0 m/s²

According to Newton's third law of motion which states that action ad reaction are equal and opposite, when the elevator moves upwards, we have;

The net force the man experiences, F = Gravitational force, m·g + The force of the elevator pushing upwards, m·a

∴ ↑F = m·g + m·a

Where;

F = The net force the man experiences

m = The mass of the man = 96 kg

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

a = The acceleration of the elevator = 4 m/s²

∴ ↑F = 96 kg × 9.8 m/s² + 96 kg × 4 m/s² ≈ 1,324.8 N

The net upward force the man experiences ≈ 1,324.8 N

When the elevator moves downwards, we have;

The net force the man experiences, F = Gravitational force, m·g + The loss of the gravitational force as the floor moves further downwards, -(m·a)

∴ F = m·g + -(m·a) = m·g - m·a

F = m·g - m·a

∴ ↓F = 96 kg × 9.8 m/s² - 96 k × 4 m/s² ≈ 556.8 N

The net downward force the man experienced ≈ 556.8 N

8 0

2 years ago

Birds resting on high-voltage power lines are a common sight. the copper wire on which a bird stands is 3.5 cm in diameter and c

kiruha [24]

Answer:

$1.0 \cdot 10^{-5}V$

Explanation:

First of all, we need to calculate the resistance of the piece of copper wire between the bird's feet, which is given by

$R=\rho \frac{L}{A}$

where:

$\rho = 1.68 \cdot 10^{-8} \Omega m$ is the resistivity of copper

$L = 2.1 cm = 0.021 m$ is the length of the piece of wire between the bird's feet

$A=\pi r^2$ is the cross-sectional area of the wire, with r being the radius. Since the radius is half the diameter:

$r=\frac{3.5 cm}{2}=1.75 cm=0.0175 m$

the area is

$A=\pi (0.0175 m)^2=9.34 \cdot 10^{-4} m^2$

And the resistance is

$R=(1.68\cdot 10^{-8} \Omega m \frac{0.0175 m}{9.34 \cdot 10^{-4} m^2}=3.15\cdot 10^{-7}\Omega$

And given the current in the wire, I=32 A, we can calculate the potential difference across the bird's body by using Ohm's law:

$V=IR=(32 A)(3.15\cdot 10^{-7} \Omega)=1.0 \cdot 10^{-5}V$

6 0

2 years ago

LA 7.0 liter balloon at room temperature (22°C) contains hydrogen gas. If the

coldgirl [10]

Answer:

Explanation: Convert temperatures to Kelvins.

22 C = 295 K

30 C = 303 K

According to Charles' law:

V1 / T1 = V2 / T2

7 / 295 = V2 / 303

V2 = (303 * 7) / 295

V2 = 7.18983 Litres which rounds to 7.19 litres.

5 0

2 years ago