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LUCKY_DIMON [66]
3 years ago
14

Astronomers believe that the universe began as an enclosed, cold object. true or false?

Physics
2 answers:
Margarita [4]3 years ago
6 0

Answer: False

Explanation:

Astronomers believe that the universe began as a point (singularity) where all the matter of the universe was enclosed. The point had infinite density and extremely high temperature. The universe started expanding at t =0 when big bang occurred. With the expansion of the universe, the temperature started reducing. Detection of Cosmic Microwave Background Radiation is in agreement with this theory.

Thus, the given statement is false.

zhannawk [14.2K]3 years ago
4 0
<span>Scientists believe that the earliest state of the universe was hot and dense. So I think this is false.</span>
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A ball is thrown horizontally at 20 m/s from the top of a cliff 50 meters high. how far from the base of the cliff does the ball
Oksanka [162]
You need to divide the motion into its component: vertical and horizontal motion.

The time taken to fall vertically from the cliff is equal to the time taken to move horizontally.

Using the vertical component, which is an accelerated motion with an initial velocity equal to zero, we can solve for t:
h = 1/2 · g · t²

t = √(2·h / g)
  = √(2·50 / 9.8)
  = 3.2 s

Horizontally, it is a constant motion:
d = v · t
   = 20 · 3.2
   = 64 m

The ball will strike the ground at a distance of 64 meters from the cliff.
6 0
3 years ago
A car travels on the entrance ramp to a freeway as it accelerates from 30 mph to the freeway speed of 70 mph for 4.0 s. Suppose
vova2212 [387]

Answer:

a) distance d = 293.36ft

b) acceleration a = 14.67ft/s^2

Explanation:

Acceleration is the change in velocity per unit time.

a = ∆v/t ....1

Given;

Initial velocity vi = 30mph × 5280ft/mile × 1/3600s/h

vi = 44ft/s

Final velocity vf = 70mph × 5280ft/mile × 1/3600s/h

vf = 102.67ft/s

time = 4.0s

From equation 1, acceleration is;

a = ∆v/t = (102.67-44)/4 = 14.67ft/s^2

Distance travelled can be given as;

d = ut + 0.5at^2 .....2

u = 44ft/s

t = 4

a = 14.67ft/s^2

Substituting into the equation 2

d = 44(4) + 0.5(14.67×4^2)

d = 293.36ft

5 0
3 years ago
After t hours a freight train is s(t) = 18t2 − 2t3 miles due north of its starting point (for 0 ≤ t ≤ 9). (a) Find its velocity
BartSMP [9]

Answer:

Explanation:

Given the equation modelled by the height of the train given as:

s(t) = 18t²-2t³ for for 0 ≤ t ≤ 9

a) Velocity is the rate of change of displacement.

Velocity = dS(t)/dt

V = dS(t)/dt = 36t - 6t² miles

Velocity at t = 3hrs is determiner by substituting t = 3 into the velocity function.

V = 36(3) -6(3)²

V= 108 - 72

Velocity = 36mi/hr

b) for Velocity at time = 7hrs

V(7) = 36(7) - 6(7)²

V(7) = 252 - 294

V(7) = -42mi/hr

The velocity at t = 7hrs is -42mi/hr

c) Acceleration is the rate of change of velocity.

a(t) = dV(t)/dt

Given v(t) = 36t - 6t²

a(t) = 36 - 12t

Acceleration at t=1 is given as:

a(1) = 36 -12(1)

a(1) = 24mi/hr²

4 0
3 years ago
Why does ice float in your drink but, your sunglasses sink in the pool?
kykrilka [37]

Answer:

cause Ice is lighter than sunglasses

4 0
3 years ago
how long does it take an acorn to hit the ground after dropping from the branch of a tree 50.0m high? remember that g=9.8m/s^2
NeX [460]
D = V1( t ) + 1/2g( t )^2
50m = 0m/s( t ) + 1/2(9.8m/s^2)*( t )^2
V1*t cancels out
50m = (4.9m/s^2)*(t)^2
50m/(4.9m/s^2) = t^2
Metres unit cancels out so we are left with s^2
10.204s^2 = t^2
Square root both sides to cancel out square
t = 3.19 s
5 0
3 years ago
Read 2 more answers
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