1 & 2 please, this is science

Which statement is true with respect to an atom?

maria [59]

The statement that is true concerning an atom would be C. The atomic number of an atom is equal to the number of protons.

7 0

3 years ago

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The flaming gorge bridge, in wyoming rises above a dry gulch. If you throw a rock straight out from the bridge, horizontally, an

Novosadov [1.4K]

Answer:

12.495m/s

Explanation:

Horizontal displacement is the range of the projectile motion.

The range is expressed as;

R = 2U/g

U is the speed at which the rock is thrown (initial speed)

g is the acceleration due to gravity.

Given

R = 255cm = 2.55m

g = 9.8m/s²

Required

Speed U

Substitute the given parameters into the formula as shown;

2.55 = 2U/9.8

Cross multiply

2U = 2.55×9.8

2U = 24.99

U = 24.99/2

U = 12.495m/s

Hence the speed that you thew the rock is 12.495m/s

7 0

3 years ago

A golf ball stays on the tee until the golf club hits it. Which of the following principles best describes why this occurs? Grou

givi [52]

Answer:

Newton's First Law of Motion.

Explanation:

Newton's first law of motion states that an object continues to stay in its state of rest, or of uniform motion, until acted upon by an external force.

So in the case of the golf ball here, the ball stays in its state of rest, on the tee, until the golf club hits it, i.e. , applies an external force on it.

Hence we can say that Newton's First Law of Motion is the principle which is most suitable for explaining this phenomenon.

7 0

4 years ago

It is winter in Puerto Rico. Compare the air temperatures beachgoers feel near the water

Leviafan [203]

Large amounts of water do have a big impact on the weather: indeed, it takes less energy to warm/cool land than water.
Therefore, places near large amounts of water tend to have smaller differences in temperature between summer and winter than places far from waters.

Hence, during winter in Puerto Rico, alongside the coast, the temperature will be higher than in the innermost parts of the island.

7 0

3 years ago

Determine the magnitude of the average friction force exerted on the collar when the velocity of the collar at c is 3.39 m/s and

djverab [1.8K]

The magnitude of the average friction force exerted on the collar (F)= 8.641 N

<h3>How can we calculate the magnitude of the average friction force exerted on the collar?</h3>

To calculate the magnitude of the average friction force exerted on the collar we are using the formula,

$\frac{1}{2} k(x^2_f - x^2_i ) + F\times y + \frac{1}{2} m v^{2} _{c} = mgy$

Here we are given,

k = The spring has a spring constant.

= 25.5 N/m.

$x_f$ = Final length of the spring .

= $\sqrt{1.25^2+1.8^2} -0.60$

= 1.591 m

$x_i$ = The initial length of the spring.

= 1.25−0.60

=0.65 m

y=The collar then travels downward a distance.

= 1.80 m.

m= The mass of the collar.

=3.55 kg

$v_c$ = the velocity of the collar.

= 3.39 m/s.

g = The acceleration due to gravity.

= 9.81 m/s²

We have to calculate the magnitude of the average friction force exerted on the collar = F

Now we put the known values in the above equation, we get;

$\frac{1}{2} k(x^2_f - x^2_i ) + F\times y + \frac{1}{2} m v^{2} _{c} = mgy$

Or, $\frac{1}{2} \times 25.5 \times((1.591)^2 - (0.65)^2 ) + F\times 1.80 + \frac{1}{2}\times 3.55\times (3.39)^{2} = 3.55\times 9.81\times 1.80$

Or, F= 8.641 N

From the above calculation we can conclude that,

The magnitude of the average friction force exerted on the collar (F)= 8.641 N

Learn more about friction:

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Question:

The 3.55 kg collar shown below is attached to a spring and released from rest at A. The collar then travels downward a distance of y = 1.80 m. The spring has a spring constant of k = 25.5 N/m. The distance a is given as 1.25 m. The datum for gravitational potential energy is set at the horizontal line through A and B. Determine the magnitude of the average friction force exerted on the collar when the velocity of the collar at c is 3.39 m/s and the spring has an unstretched length of 0.60 m .

6 0

2 years ago