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3 years ago

The atomic mass of an element whose atoms consist of seven protons, eight neutrons, and seven electrons is _____?

2 answers:

6 0

The atomic mass is C. 15

Atomic mass = P + N = 7+8 = 15

The atomic mass of an element is defined as the sum of the protons and neutrons. On the other hand, the atomic number of a neutral element is equivalent to the number of protons or electrons. This is because a neutral element should have equal number of protons and electrons.

MrRissso [65]3 years ago

3 0

Answer:

Explanation:

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People have proposed driving motors with the earth's magnetic field. This is possible in principle, but the small field means th

fiasKO [112]

Answer:

636.619772368 A

Explanation:

$\tau$ = Torque = $1\times 10^{-3}\ N/m$

B = Magnetic field of Earth = $5\times 10^{-5}\ T$

A = Area

d = Diameter = 20 cm

Current is given by

$I=\dfrac{\tau}{BA}\\\Rightarrow I=\dfrac{1\times 10^{-3}}{5\times 10^{-5}\times \dfrac{\pi}{4}\times 0.2^2}\\\Rightarrow I=636.619772368\ A$

The current is 636.619772368 A

8 0

3 years ago

A ball is thrown straight up. If the launch velocity is 15 m/s, at what SPEED will the ball return to the thrower’s hand?

IgorC [24]

Answer:

Vf = 15 m/s

Explanation:

First we consider the upward motion of ball to find the height reached by the ball. Using 3rd equation of motion:

2gh = Vf² - Vi²

where,

g = acceleration due to gravity = -9.8 m/s² (negative sign for upward motion)

h = height =?

Vf = Final Velocity = 0 m/s (Since, ball momentarily stops at highest point)

Vi = Initial Velocity = 15 m/s

Therefore,

2(-9.8 m/s²)h = (0 m/s)² - (15 m/s)²

h = (-225 m²/s²)/(-19.6 m/s²)

h = 11.47 m

Now, we consider downward motion:

2gh = Vf² - Vi²

where,

g = acceleration due to gravity = 9.8 m/s²

h = height = 11.47 m

Vf = Final Velocity = ?

Vi = Initial Velocity = 0 m/s

Therefore,

2(9.8 m/s²)(11.47 m) = Vf² - (0 m/s)²

Vf = √(224.812 m²/s²)

8 0

3 years ago

The change of motion of a body is proportional to the applied force, and it takes place in the direction of a straight line in w

7nadin3 [17]

Answer:

Newton's Second Law of Motion

Explanation:

According to Newton's second law of motion, the change in velocity of a body is directly proportional to the force applied on it. Velocity is a vector quantity. It measures the magnitude of the speed as well as its direction.

F = m a

where, F is the applied force, m is the mass and a is the acceleration.

It can also be expressed as:

$F = \frac{dp}{dt}$