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4 years ago

Suppose a supernova occurs in a star that initially had 10 solar masses. why would the likely end result not be a black hole?

1 answer:

7 0

When a supernova occurs, a very large portion of the stars' mass is lost. In order to create a black hole, at least 30 solar masses is needed, so starting with 10 and losing a large portion of that mass is nowhere near enough to create a black hole. The end result would be a Neutron star.

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A car is traveling north at 17.7 m/s . After 6 it’s velocity is 141 in the same direction. Find the magnitude and direction of t

Furkat [3]

By equation of motion we have v = u + at

Where u = Initial velocity, v = final velocity, t = time taken and a = acceleration

Here v = 141 m/s, u = 17.7 m/s and t = 6 s

On substitution we will get

141 = 17.7+ 6a

So, a = (141-17.7)/6 = 20. 55 m/ $s^{2}$

Aceeleration = 20. 55 m/ $s^{2}$ along north direction.

3 0

4 years ago

Two equal forces are applied to a door. The first force is applied at the midpoint of the door, the second force is applied at t

Orlov [11]

Answer:

D) the second at the doorknob

Explanation:

The torque exerted by a force is given by:

$\tau = Fdsin \theta$

where

F is the magnitude of the force

d is the distance between the point of application of the force and the centre of rotation

$\theta$ is the angle between the direction of the force and d

In this problem, we have:

- Two forces of equal magnitude F

- Both forces are perpendicular to the door, so $\theta=90^{\circ}, sin \theta=1$

- The first force is exerted at the midpoint of the door, while the 2nd force is applied at the doorknob. This means that d is the larger for the 2nd force

--> therefore, the 2nd force exerts a greater torque

4 0

3 years ago

Compare and contrast static, sliding, and rolling friction.

Mama L [17]

Static friction - the friction that occurs when a force is being applied on a still object.

Sliding friction - the friction that occurs upon a moving object; it is always lower than the static friction of the same object.

Rolling friction - the friction on a rolling object; it is actually a form of static friction with the contact point of the wheel with the surface.

4 0

4 years ago

in a tall building, a certain window is 500 meters above the ground.A tennis ball is catapulted horizontally out of the window w

expeople1 [14]

The tennis ball lands at a point 40.4 m from the base of the building.

The tennis ball is projected with a horizontal velocity u from a window, which is at a height y from the ground. The ball lands at a distance x from the base of the building. Let the ball take a time t to reach the ground. In the time t ,the ball falls a vertical distance y and also travel a horizontal distance x.

The initial vertical velocity of the ball is zero, since the ball is projected in the horizontal direction. The ball falls down under the action of gravitational force.

Thus, use the equation of motion,

$y=\frac{1}{2} gt^2$

rewrite the expression for t and calculate the value of t using 9.81 m/s²for g and 500 m for y.

$t=\sqrt{\frac{2y}{g} } \\ =\sqrt\frac{(2)(500m)}{9.81m/s^2} \\ =10.096 s$

The horizontal distance x is traveled using the constant velocity u since no force acts on the ball in the horizontal direction.

Therefore,

$x=ut$

Substitute 4 m/s for u and 10.096 s for t

$x=ut\\ =(4m/s)(10.096s)\\ =40.384m=40.4 m$

Thus, the ball lands at a point 40.4 m from the base of the building.

6 0

4 years ago

Focus Question: How are physical properties used to compare and classify substances?

Kisachek [45]

Answer:

Properties that can be determined without changing the composition of a substance are referred to as physical properties. Characteristics such as melting point, boiling point, density, solubility, color, odor, etc. ... Physical and chemical properties can be used to classify a substance as ionic or molecular.

Explanation:

Hope it helps! Correct me if I am wrong!

Dont worry im sure about my answer!

If you dont mind can you please mark me as brainlest?

Its ok if you don't want to!

8 0

3 years ago