Which planet has a density that is less than the density of liquid water?

A lead ball is dropped 30 feet from a church tower. If the acceleration due to gravity is 9.8m s^-2, how long does it take the b

Alika [10]

final velocity of a falling object = 0

and acceleration of a falling object is negative

now using the expression ( Newton's 3rd equation of motion)

${v}^{2} = {u}^{2} - 2gs$

where the parameters have their usual meaning

making

${u}^{2} \: the \: subject$

thus

${u}^{2} = 2gs$

$u = \sqrt{2gs}$

from the question,

g= 9.8m/s^2

s = 30m

substitute them into the equation

$u = \sqrt{2(9.8 \times 30)}$

$u = \sqrt{588}$

u = 24.25m/s

but the question is demanding for time but not the initial velocity

so substitute them in the

Newton's first equation of motion

where

V = u - gt

but from the question,

v= 0 and the acceleration is negative because it's a free fall

substitute the values into the equation

0 = 24.24 -9.8t

making t the subject

9.8t = 22.24

dividing through by 9.8

9.8t/9.8 = 22.24/9.8

t = 2.3s . therefore, it would take 2.3s for the ball to hit the ground.

4 0

4 years ago

A plastic sphere floats in water with 50.0% of its volume submerged. This same sphere floats in glycerin with 40.0% of its volum

Natasha_Volkova [10]

Explanation:

weight of water displaced=weight of sphere,

Since, plastic sphere floats in water with 50.0% of its volume submerged

so, water=2 sphere,

so sphere's density = 1/2 of water's density

Now, weight of glycerin displaced=weight of sphere,

Also given This same sphere floats in glycerin with 40.0% of its volume submerged.

so glycerin =2.5 sphere,

so sphere's density = .4 of glycerin's = 1/2 of water's.

So glycerin = 1.25 water

6 0

3 years ago

A car traveling on a flat (unbanked), circular track accelerates uniformly from rest with a tangential acceleration of 1.85 m/s2

Tasya [4]

Answer:

Coefficient of friction = 0.836

Explanation:

If v be the speed after one quarter of the circular path

v² = 2as = 2 x 1.85 x 2πr/4 ; v²/r = 1.85 x 3.14 = 5.8

tangential acceleration = 5.8 m/s²

radial acceleration = v² /r = 5.8

total acceleration = √2 x 5.8

m x√2 x 5.8 = m x g xμ

μ = √2 x 5.8 / 9.8 = 0.836

7 0

3 years ago

Because of its center-surround organization, a neuron that has its entire receptive field exposed to bright light will:

Tom [10]

Answer:

b. maintain the same rate of firing as if there was no light presented.

Explanation:

The neuron will maintain the same rate of firing as if there was no light presented.

Receptive filed of neuron is place on its sensory surface generally on the back of eye that an stimulus must reach to activate the neuron. The bright light cannot change the rate of firing of the neuron.

5 0

4 years ago

Please help me out

Licemer1 [7]

Answer:

C

Explanation:

Because you would need to be able to handle the weight to move it.

3 0

4 years ago