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3 years ago

8TH GRADE SCIENCE I NEED NOW DO NOT SKIP

Physics

1 answer:

yan [13]3 years ago

7 0

Explanation:

1. Force=mass*acceleration

acceleration=force/mass

=100/50

=2m/s^2

2. Gravitational force for downward acceleration= mg-ma=m(g-a) , since a is less than g,

So it will be= 50(9.8-2)

=50(7.8)= 390N

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The triceps muscle in the back of the upper arm extends the forearm. This muscle in a professional boxer exerts a force of 2.00

xenn [34]

Answer:

$0.496 kg m^2$

Explanation:

The torque exerted is given by

$\tau = Fd$

where

$F=2.00 \cdot 10^3 N$ is the force applied

d = 3.10 cm = 0.031 m is the length of the lever arm

Substituting,

$\tau=(2.00\cdot 10^3 N)(0.031 m)=62 Nm$

The equivalent of Newton's second law for rotational motion is:

$\tau = I \alpha$

where

$\tau = 62 Nm$ is the net torque

I is the moment of inertia

$\alpha = 125 rad/s^2$ is the angular acceleration

Solving the equation for I, we find

$I=\frac{\tau}{\alpha}=\frac{62 Nm}{125 rad/s^2}=0.496 kg m^2$

6 0

3 years ago

What is the result of 1.58 divided by 3.793 written with the correct number of significant figures?

NISA [10]

0.41655681518586870551015027682573

8 0

2 years ago

Eye at the lowest radiated power of 1,2 x10 x (- 17) W. Determine how many photons of light with a wavelength of 500nm fall on t

mars1129 [50]

Answer:

$\frac{n}{t} = 30\ photons/s$

Explanation:

The radiated power can be given in terms of the wavelength as follows:

$Rasiated\ Power = \frac{nE}{t} = \frac{nhc}{\lambda t}$

where,

Radiated Power = 1.2 x 10⁻¹⁷ W

n = no. of photons = ?

h = plank's constant = 6.625 x 10⁻³⁴ J.s

c = speed of light = 3 x 10⁸ m/s

λ = wavelength = 500 nm = 5 x 10⁻⁷ m

t = time

Therefore,

$1.2\ x\ 10^{-17}\ W = \frac{n(6.625\ x\ 10^{-34}\ J.s)(3\ x\ 10^8\ m/s)}{(5\ x\ 10^{-7}\ m)(t) }\\\\\frac{n}{t} = \frac{1.2\ x\ 10^{-17}\ W}{3.975\ x\ 10^{-19}\ J}\\\\\frac{n}{t} = 30\ photons/s$

8 0

2 years ago

Give an example of a collision in real life. Use the law of conservation of energy to describe the transfer of momentum. Be sure

ozzi

Explanation :

Using the law of conservation of energy

When two cars collide with each other then the momentum is same before collision and after collision but energy is changed after collision in form of heat and sound.

We know this collision is inelastic collision.

In Inelastic collision, when two objects collide with each other then the momentum is conserved but kinetic energy is not conserved.

7 0

3 years ago

a 0.311 kg tennis racket moving 30.3 m/s east makes an elastic collision with a 0.0570 kg ball moving 19.2 m/s west. find the ve

Colt1911 [192]

Answer:

15.0 m/s

Explanation:

When elastic collision occurs, the final velocities, v of the bodies are obtained by

$v_1=\frac {(m_1-m_2)u_1}{m_1+m_2}+ \frac {2m_2u_2}{m_1+m_2}$

$v_2=\frac {(m_2-m_1)u_2}{m_1+m_2}+ \frac {2m_2u_1}{m_1+m_2}$

Where u and m denote initial velocities and mass while the subscripts 1 and 2 are for tennis ball and the other ball

Substituting 0.311 for mass of tennis, 0.0570 for mass of the other ball, 30.3 m/s for velocity of tennis ball and -19.2 m/s

$v_1=\frac {(0.311-0.0570)\times 30.3}{0.311+0.0570}+ \frac {2\times 0.0570\times -19.2}{0.311+0.0570}= 20.91359+ -5.94783= 14.96576 m/s\approx 15.0 m/s$

3 0

3 years ago