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3 years ago

12. What does positive and negative acceleration indicate?

Physics

1 answer:

Vesnalui [34]3 years ago

4 0

Answer:

Correct answer: positive acceleration indicates accelerated movement (motion) and negative acceleration indicates slow movement (motion)

Explanation:

v = v₀ + a t accelerated movement

v = v₀ - a t slow movement

God is with you!!!

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What type of force keeps the Earth in orbit around the Sun?

faust18 [17]

The answer is the suns gravity

5 0

4 years ago

A new event has been proposed for the Winter Olympics. An athlete will sprint 100 m, starting from rest, then leap onto a 20 kg

Mamont248 [21]

Answer:

3.5 m

Explanation:

Given

Mass of the bob sled , m_b = 20 kg

Mass of the girl, m = 40 kg

Speed of the girl, v = 12 m/s

Spring constant , k = 2000 N/m

Length of the ramp, L = 50 m

Angle of incline , θ = 20°

When the girl leaps on the sled , we use conservation of momentum principle

to find the speed of sled and the girl

m v + m_b (0) = (m + m_b) v_1

40 kg ×12 m/s = (20 kg + 40 kg ) v_1

v_1= 8 m/s

----------------------------------------------------------------------------

The height of the incline is ,

h = L sin 20 = 50 m sin 20° = 17.1 m

By law of conservation of energy

(m + m_b) g h + 1/2 (m + m_b) v_1^2 = 1/2 (m +m_b) v2^2 + 1/2 k x^2

(60 kg ) ×9.8 m/s^2 ×17.1 m + 1/2 (60 kg ) (8 m/s)^2 = 1/2 (m +m_b)(0)^2 +1/2(2000 N/m) x^2

x = 3.5 m

Thus, the compression in the spring is 3.5 m

5 0

4 years ago

An object is thrown horizontally off a cliff with an initial velocity of 5.0 meters per second. The object strikes the ground 3.

vladimir2022 [97]

The acceleration of gravity is 9.8 m/s². This simply means that when anything falls, its downward speed keeps increasing, and it falls 9.8 m/s faster every second than it fell 1 second earlier.

After 3 seconds of falling, the object is falling at (3 x 9.8 m/s) = 29.4 m/s faster than at the beginning of the 3 seconds. If it had no vertical speed at the beginning of the 3 seconds, then THAT's its speed after 3 seconds . . . . . <em>29.4 m/s</em> downward.

As far as being thrown horizontally off the cliff . . . that has no effect on it vertical speed. Horizontally, it doesn't matter whether it rolls gently over the edge, or somebody throws it horizontally, or it gets shot horizontally out of a high power rifle. It hits the ground at the same time and with the same speed in every case.

6 0

3 years ago

Read 2 more answers

a filament lamp is at full brightness with a potential difference of 12v across it. If a current of 1.8A flows through the lamp.

kvasek [131]

To find resistance you have to divide Volts by Amps.
So 12/1.8 would give you 6.67 ohms.
I hoped this helped.

5 0

4 years ago

A green block of mass m slides to the right on a frictionless floor and collides elastically with a red block of mass M which is

igor_vitrenko [27]

Answer: M is equal to m.

Explanation:

The question gives us two important informations:

M is initially at rest
m finishes at rest after collision.

In any collision, as it is asumed that no external forces can act during the collision, momentum must be conserved.

So, if we call p₁ to the momentum before collision, and p₂ to momentum after it, taking into account the information above, we can write the following:

p₁ = mv₁ + M.0 = p₂ = m.0 + Mv₂ ⇒ mv₁ = Mv₂

From the question, we also know that it was an elastic collision.

In elastic collision, added to the momentum conservation, it must be conserved the kinetic energy also.

So, if we call k₁ to the kinetic energy prior the collision, and k₂ to the one after it, we can write the following:

k₁ = 1/2 m(v₁)² + 1/2 M.0 = k₂ = 1/2m.0 + 1/2M(v₂)² ⇒ m(v₁)² = M(v₂)²

Mathematically, the only way in which both equations be true, should be with v₁ = v₂, which is only possible if m=M too.

In this type of collision, it is said that the energy transfers from one mass to the other.

7 0

3 years ago