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4 years ago

In the symbol 4/2He the subscript 4 is the _____for helium and 2 is the subscript for helium

1 answer:

7 0

$^{4}_{2}}He$
The 4 signifies the atomic weight, and the 2 subscribes the element's atomic number(aka the number of protons in the atom).

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A force has direction and contact

dalvyx [7]

Answer:

A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newton (N). Force is represented by the symbol F. The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time.

Other units: dyne, pound-force, poundal, kip, kilopond

SI unit: newton (N)

Common symbols: F→, F, F

7 0

3 years ago

The amount of energy in food is measured in

mr Goodwill [35]

The amount of energy in food is measured in calories.
Wats and kilowatts are units for electricity. Grams are a unit of mass.

3 0

3 years ago

A sound wave with a waveenght of 2.5 meters traves 660 meters in 2 seconds calculate the frequemcy of the wave to cacuation the

finlep [7]

The frequency of the wave is 132 Hz

Explanation:

To calculate the speed of the wave, we can use the following formula:

$v = \frac{d}{t}$

where

d is the distance travelled by the wave

t is the time elapsed

For the sound wave in this problem, we have:

d = 660 m is the distance travelled

t = 2 s is the time interval considered

Substituting and solving for v, we find the speed of the sound wave:

$v=\frac{660}{2}=330 m/s$

Now we can calculate the frequency of the wave by using the wave equation:

$v=f\lambda$

where

v = 330 m/s is the speed of the wave

$\lambda=2.5 m$ is the wavelength

f is the frequency

Solving for f, we find:

$f=\frac{v}{\lambda}=\frac{330}{2.5}=132 Hz$

Learn more about wavelength and frequency:

brainly.com/question/5354733

brainly.com/question/9077368

#LearnwithBrainly

7 0

3 years ago

600 kg elephant runs at 5 m/s and jumpts onto a 100kg cart. If the coefficient of friction is .04 how far will the cart travel o

Minchanka [31]

Answer:

Eleven seconds.

Explanation:

Two keys are needed to solve this problem. First, the conservation of momentum: allowing you to calculate the cart's speed after the elephant jumped onto it. It holds that:

$m_ev_e+m_c\cdot0=(m_e+m_c)v_0\implies \\v_0=\frac{m_ev_e}{m_e+m_c}=\frac{600kg\cdot 5\frac{m}{s}}{700kg}=4.29\frac{m}{s}$

So, once loaded with an elephant, the cart was moving with a speed of 4.29m/s.

The second key is the kinematic equation for accelerated motion. There is one force acting on the cart, namely friction. The friction acts in the opposite direction to the horizontal direction of the velocity v0, its magnitude and the corresponding deceleration are:

$F_r = 0.04\cdot (m_e+m_c)g\implies a_r = 0.04\cdot g= 0.04 \cdot 9.8 \frac{m}{s^2}=0.39\frac{m}{s^2}$

The kinematic equation describing the decelerated motion is:

$v = -a_r t+v_0\\0 = -a_rt+v_0\implies \\t = \frac{v_0}{a_r}=\frac{4.29\frac{m}{s}}{0.39\frac{m}{s^2}}=11s$

It takes 11 seconds for the comical elephant-cart system to come to a halt.

7 0

3 years ago

Which of these statements best explains why trees in a forest do not grow very close to one another?

SpyIntel [72]

Answer: trees compete for resources directly around them .

7 0

3 years ago

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