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3 years ago

29:45

Physics

2 answers:

Ostrovityanka [42]3 years ago

8 0

Answer:

It closes the circuit so that electric charges do not flow to the timer

Explanation:

It's common sense.... lol!!!

Yakvenalex [24]3 years ago

6 0

Answer:

it opens the circuit so that electric charges do not flow to the timier

Explanation: a closed circut will allow electrisity to flow through.

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Two people push on a boulder to try to move it. The mass of the boulder is 815 kg. One person pushes north with a force of 65 N.

ivanzaharov [21]

Answer:

$0.095 m/s^2$

Explanation:

As the 2 force directions are perpendicular (North vs West), we can calculate the magnitude of the net force using the following equation

$F = \sqrt{65^2 + 42^2} = 77.4 N$

Assuming negligible friction, from here we can calculate the acceleration in accordance to Newton's 2nd law of motion

$a = F/m = 77.4 / 815 = 0.095 m/s^2$

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3 years ago

Rills, gullies, streams, rivers and tributaries are all caused by

Gnom [1K]

<span>Rills, gullies, streams, rivers and tributaries are all caused by water erosion. Water erosion is the natural act by which water flow (or wind flow) slowly removes soil, rock, or any material found in the earth's crust. The removed materials are transported to another location, leaving behind changes in the crust.</span>

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3 years ago

A child throws a baseball directly upward. What are the signs of the velocity and acceleration of the ball at the very top of th

Anastaziya [24]

Answer:

velocity zero and acceleration negative

Explanation:

According to the directions taken in the vector analysis, the direction which is upwards taken as positive, the direction which is downwards is taken as negative.

The direction which is rightwards taken as positive and the direction which is leftwards taken as negative.

here, ball throws vertically upwards and it attains a maximum height. At maximum height the magnitude of velocity is zero but the acceleration is always acting downwards so it is taken as negative in sign.

3 0

3 years ago

A ball with mass of 0.050 kg is dropped from a height of h1 = 1 .5 m. It collides with the floor, then bounces up to a height of

Iteru [2.4K]

Answer:

Explanation:

Impulse of reaction force of floor = change in momentum

Velocity of impact = √ 2gh₁

= √ 2 x 9.8 x 1.5 = 5.4 m /s.

velocity of rebound = √2gh₂

= √ 2x 9.8 x 1

= 4.427 m / s.

Initial momentum = .050 x 5.4 = .27 kg m/s

Final momentum = .05 x 4.427 = .22 kg.m/s

change in momentum = .27 - .22 = .05 kg m/s

Impulse = .05 kg m /s

Impulse = force x time

force = impulse / time

.05 / .015 = 3.33 N.

kinetic energy = 1/2 m v²

Initial kinetic energy = 1/2 x .05 x 5.4²

= 0.729 J

Final Kinetic Energy =1/2 x .05 x 4.427²

= 0.489 J

Change in Kinetic energy =0 .24 J

Lost kinetic energy is due to conversion of energy into sound light etc.

4 0

4 years ago

A driver brings a car to a full stop in 2.0 s. If the car was initially

vagabundo [1.1K]

Answer:

$\boxed {\boxed {\sf D. \ -11 \ m/s^2}}$

Explanation:

Acceleration can be found by dividing the change in velocity by the time.

$a=\frac{v_f-v_i}{t}$

where Vf is the final velocity, Vi is the initial velocity, and t is the time.

Since the car came to a complete stop, it's final velocity was 0 meters per second.

The initial velocity was 22 meters per second.

The time was 2.0 seconds.

$v_f=0 \ m/s\\v_i=22 \ m/s\\t= 2.0 \ s$

Substitute the values into the formula.

$a=\frac{0 \ m/s-22 \ m/s}{ 2.0 \s }$

Subtract in the numerator first.

0 m/s- 22 m/s = -22 m/s

$a=\frac{-22 \ m/s}{2.0 \ s}$

Divide.

$a= -11 \ m/s^2$

The acceleration of the car was -11 meters per square second. The negative acceleration indicates slowing down/stopping.

8 0

3 years ago