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3 years ago

Kelly sits on a rock. Her weight is an action force. What is the reaction force?

1 answer:

4 0

The force ffrom the ground that holds the rock up and prevents her from falling through the gound, unless the ground breaks.

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A quarterback throws a football toward a receiver with an initial speed of 20 m/s at an angle of 30∘ above the horizontal. At th

lana66690 [7]

Answer:

a) In order to catch the ball at the level at which it is thrown in the direction of motion.

b)Speed of the receiver will be 7.52m/s

Explanation:

Calculating range,R= Vo^2Sin2theta/g

R= (20^2×Sin(2×30)/9.8 = 35.35m

Let receiver be(R-20) = 35.35-20= 15.35m

The horizontal component of the ball is:

Vox= Vocostheta= 20× cos30°

Vox= 17.32m/s

Time taken to coverR=35.35m with 17.32m/s will be:

t=R/Vox= 35.35/17.32

t= 2.04seconds

b)Speed required to cover 15.35m at 2.04seconds

Vxreciever= d/t = 15.35/2.04 = 7.52m/s

7 0

2 years ago

Read 2 more answers

1.D 2.A 3.A 4.im not sure please help 5.false One light bulb in a string of lights goes out. This causes all of the other lights

bezimeni [28]

4.Use Ohm’s Law to determine the resistance in a circuit if the voltage is 12.0 volts and the current is 4.0 amps.

A. 8.0 ohms B. 48 ohms C. 3.0 ohms D. 12 ohms

Ohm's law is V=IR, or I=V/R, or R=V/I. (I= current, V= voltage, R= resistance.) Let's plug in our variables: V=12.0, I=4.0, R=? into the equation R=V/I. 12.0/4.0=3.0, so the resistance is 3.0 ohms.

6 0

3 years ago

PLSS HELP AND I WILL GIVE BRAINLY TO THE ONE WHO ANSWERS CORRECTLY

Ierofanga [76]

The potential difference,electric current ,resistance and new electric current will be 12 V,4 A,3 Ω,2 A.

<h3>What is resistance?</h3>

Resistance is a type of opposition force due to which the flow of current is reduced in the material or wire. Resistance is the enemy of the flow of current.

The energy in terms of the charge and potential difference is;

E= qV

60=5 C × V

V= 12 V

The electric current is found as;

$\rm I= \frac{q}{t} \\\\ I= \frac{5}{1.25}\\\\ I=4 \ A$

From the ohm's law;

V=IR

12=4 ×R

R=3Ω

If the voltage is constant and the resistance is doubled, then the new electric current is half of the previous condition;

$\rm I'=\frac{I}{2} \\\\ I'=\frac{4}{2} \\\\\ I'=2 \ A$

Hence, the potential difference,electric current ,resistance and new electric current will be 12 V,4 A,3 Ω,2 A.

To learn more about the resistance, refer to the link;

brainly.com/question/20708652

#SPJ1

7 0

1 year ago

Two blocks are attached to opposite ends of a massless rope that goes over a massless, frictionless, stationary pulley. One of t

Marysya12 [62]

Answer:

Explanation:

Find the diagram attached for better understanding of the question.

Given the mass of one of the blocks to be 1.0kg and accelerates downward at 3/4g.

g = acceleration due to gravity.

Let the block accelerating downward be M, mass of the other body be 'm' and the acceleration of the body M be 'a'.

M = 1.0 kg and a = 3.4g

According to newton's second law; $\sum fy = ma_y$

For body of mass m;

T - mg = ma ... (1)

For body of mass M;

Mg - T = Ma ... (2)

Adding equation 1 ad 2;

+Mg -mg = ma + Ma

Ma-Mg = -mg-ma

M(a-g) = -m(a+g)

Substituting M = 1.0 kg and a = 3/4g into the resulting equation;

3/4 g-g = -m(3/4 g+g)

3/4 g-g = -m(7/4 g)

-g/4 = -m(7/4 g)

1/4 = 7m/4

28m = 4

m = 1/7 kg

Therefore the mass of the other box is 1/7 kg

3 0

2 years ago

A microwave oven operates at 2.4 GHz with an intensity inside the oven of 2300 W/m2 . Part A What is the amplitude of the oscill

Tasya [4]

Answer:

The amplitude of the oscillating electric field is 1316.96 N/C

Explanation:

Given;

frequency of the wave, f = 2.4 Hz

intensity of the wave, I = 2300 W/m²

Amplitude of oscillating magnetic field is given by;

$B_o = \sqrt{\frac{2\mu_o I}{c} }$

where;

μ₀ is permeability of free space = 4π x 10⁻⁷ m/A

I is intensity of wave

c is speed of light = 3 x 10⁸ m/s

$B_o = \sqrt{\frac{2*4\pi *10^{-7}*2300}{3*10^8} } \\\\B_o = 4.3899 *10^{-6} \ T$

The amplitude of the oscillating electric field is given by;

E₀ = cB₀

E₀ = 3 x 10⁸ x 4.3899 x 10⁻⁶

E₀ = 1316.96 N/C

Therefore, the amplitude of the oscillating electric field is 1316.96 N/C

3 0

2 years ago