PHYSICS HIGH SCHOOL

A skateboarder has an acceleration of -1.9 m/s2. If her initial speed is 6 m/s how long does it take her to stop?A. 4.1s
B. 3.2s
C. 0.32s
D. 2.1s

Answers

Answer 1
Answer: intial speed = 6m/s
final speed = 0 m/s as it stop
acceleration = 1.9 m/s2
time taken = t s

v=u+at
0=6+1.9*t
t=3.15 s = 3.2 s

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Two identical beakers with the same volume of water are placed on each pan of a double-pan balance. A steel ball is suspended from a string and submerged in the water of one of the containers. A hollow plastic ball of the same volume is submerged in the water of the other container and fastened to the bottom of the beaker by a string. Will the balance move, and if so in which direction?
If a ball was thrown upward at 46.3 m/s how long would the ball stay in the air
Sign of the charge???A glass marble is rubbed against a piece of silk. As a result the piece of fabric acquires extra electrons. What happens to the glass marble? (a)The marble has lost the same number of electrons acquired by the piece of silk. (b)The marble has acquired the same number of electrons acquired by the piece of silk. (c)The marble acquires a positive charge and repels the piece of silk. (d)The marble acquires a positive charge and attracts the piece of silk. (e)The marble acquires a negative charge and attracts the piece of silk. (f)The marble acquires a negative charge and repels the piece of silk. There may be more than one answer.
When you turn on the light switch in a room, you have completed the _____. open circuit series circuit parallel circuit switch circuit
A uniform Capillary tube closed at one end Contain dry air trapped by a thread of mercury 8.5x10 m long when the tube was held horizontally, the length of the air Column 5.0X10^2 Wher it held verti cally with the closed end downward the length was 4.5x10^2m Determine the value of atmospheric pressure take g=10m/s, density of mercury (1.36×10^4kg/m) ​

At which point in the life cycle of a star does nuclear fusion begin?A. Black hole
B. Main sequence
C. Nebula
D. Protostar

Answers

I would say B : main sequence is the answer . this is the answer i believe because the star will increase in size and than shine brightly and when it's done , it will get smaller turning into  nebula , eventually exploding sometime around the last stage , but not the last stage of b , c, or d

i really hope that this helps you a lot.

Final answer:

The correct answer is D. Protostar.

Nuclear fusion in a star's lifecycle begins during the protostar stage. This is when the temperature and pressure of the protostar ignite nuclear fusion, transitioning into a main sequence star.

Explanation:

In the life cycle of a star, nuclear fusion begins when the star has reached the protostar stage. The initial stage in the development of a star is the nebula, which is a cloud of dust and gas. Over time, the nebula's materials collapse under gravity to form a hot core known as a protostar.

When the protostar's temperature and pressure rises, it triggers nuclear fusion and the star begins turning hydrogen into helium.

This marks the transition from a protostar to a main sequence star, which is the stage of stable nuclear fusion.

Learn more about Nuclear Fusion in Stars here:

brainly.com/question/34526270

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Ann (mass 50 kg) is standing at the left end of a 15-m-long, 500 kg cart that has frictionless wheels and rolls on a frictionless track. Initially both Ann and the cart are at rest. Suddenly, Ann starts running along the cart at a speed of 5.0m/srelative to the cart.How far will Ann have run relative to the ground when she reaches the right end of the cart?
Express your answer with the appropriate units.

Answers

Answer:

13.5 m

Explanation:

M = Mass of cart = 500 kg

m = Ann's mass = 50 kg

v_m = Velocity of Ann relative to cart = 5 m/s

v_M = Velocity of Cart relative to Ann

As the linear momentum of the system is conserved

Mv_M+mv_m=0\n\Rightarrow v_M=-(mv_m)/(M)\n\Rightarrow v_M=-(50* 5)/(500)\n\Rightarrow v_M=-0.5\ m/s

Time taken to reach the right end by Ann

Time=(Distance)/(Speed)\n\Rightarrow Time=(15)/(5)=3\ s

Distance the cart will move in the 3 seconds

Distance=Speed* Time\n\Rightarrow Distance=-0.5* 3=-1.5\ m

The negative sign indicates opposite direction

Movement of Ann will be the sum of the distances

15+(-1.5)=13.5\ m

The net movement of Ann is 13.5 m

Barycenter can be described as?? A) the center of a celestial object
B) the point between 2 objects that is in the exact center
3) the point between 2 objects where they balance each other

Answers

Answer: 3) the point between 2 objects where they balance each other

Explanation:

The center of mass of two bodies about which the bodies orbit and balance each other is known as Barycenter. It is the point of balance of two or more celestial bodies. The Barycenter determines the orbit of the celestial bodies.

For example: the binary stars orbit a common center of mass. Pluto and its moon Charon revolve about their Barycenter.

Hence, the correct option is 3.

If frequency is kept constant, how are the velocity and wavelength of a wave related?

Answers

Answer;

Velocity and wavelength are directly proportional when frequency is kept constant.

Explanation;

  • Frequency of a wave is the number of complete oscillations made by a given wave in one second.
  • Wavelength on the other hand, is the distance between two successful crests or troughs in a transverse wave or two successful rarefactions or compressions in a longitudinal waves.
  • The speed of a wave is given by the product of the frequency of a wave and the wavelength.
  • Speed = Frequency × wavelength,
  • Therefore, if frequency is kept constant, then the speed of a wave is directly proportional to the wavelength, such that an increase in wavelength increases the speed of the wave and vice versa.

Forces contribute to the net force on a car rolling down a ramp. a. Which force supports the car’s weight?
b. Which force accelerates the car down the ramp?
c. Which force acts against the motion of the car?

Answers

B)Gravity pulls the car downward, also its the only force in the downward direction.
 C)Force that acts against is friction.

Kuiper Belt objects are composed of which substances? Select all that apply.A. Iron
B. Silicon
C. Water
D. Methane
E. Ammonia

Answers

IM sure there is C, D, and E in kuiper belts, but not really sure of silicon and iron
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