All categories

3 years ago

What is the mass of a bird if it has a potential energy of 147J when flying at a height of 30 m above the ground?

Physics

1 answer:

Artist 52 [7]3 years ago

5 0

Answer:

0.5kg

Explanation:

Given parameters:

Potential energy = 147J

Height = 30m

Unknown:

Mass of the bird = ?

Solution:

Potential energy is the energy due to the position of a body. Now, the expression for finding the potential energy is given as;

P.E = mgH

m is the mass

g is the acceleration due to gravity = 9.8m/s²

H is the height

147 = m x 9.8 x 30

m = 0.5kg

You might be interested in

Is it accurate to describe the physical universe as composed of only matter and energy?

Dennis_Churaev [7]

Yes, it is <span>accurate to describe the physical universe as composed of only matter and energy. Some people might argue about the dark matter, but it is not yet defined properly. Different universes can be made up of different compositions but it is a fact that our universe is made of matter and energy. </span>

7 0

3 years ago

Read 2 more answers

An object is placed in front of a diverging lens, such that the object-to-image distance is 71 cm.

Pachacha [2.7K]

Explanation:

Given that,

Object-to-image distance d= 71 cm

Image distance = 26 cm

We need to calculate the object distance

$u -v= d$

$u=71+26=97\ cm$

We need to calculate the focal length

Using formula of lens

$\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$

put the value into the formula

$\dfrac{1}{f}=\dfrac{1}{-26}+\dfrac{1}{97}$

$\dfrac{1}{f}=-\dfrac{71}{2522}$

$f=-35.52\ cm$

The focal length of the lens is 35.52.

(B). Given that,

Object distance = 95 cm

Focal length = 29 cm

We need to calculate the distance of the image

Using formula of lens

$\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$

Put the value in to the formula

$\dfrac{1}{-29}=\dfrac{1}{v}-\dfrac{1}{95}$

$\dfrac{1}{v}=\dfrac{1}{-29}-\dfrac{1}{95}$

$\dfrac{1}{v}=-\dfrac{124}{2755}$

$v=-22.21\ cm$

We need to calculate the magnification

Using formula of magnification

$m=\dfrac{v}{u}$

$m=\dfrac{22.21}{95}$

$m=0.233$

The magnification is 0.233.

The image is virtual.

Hence, This is the required solution.

4 0

3 years ago

A motorboat traveling 4 m/s, East encounters a current traveling 3.0 m/s, North. a) What is the resultant velocity of the motorb

Nostrana [21]

Explanation:

It is given that,

Velocity in East, $v_1=4\ m/s$

Velocity in North, $v_2=3\ m/s$

(a) The resultant velocity is given by :

$v=\sqrt{4^2+3^2}=5\ m/s$

(b) The width of the river is, d = 80 m

Let t is the time taken by the boat to travel shore to shore. So,

$t=\dfrac{d}{v}$

$t=\dfrac{80\ m}{5\ m/s}$

t = 16 seconds

(c) Let x is the distance covered by the boat to reach the opposite shore. So,

$x=v_2\times t$

$x=3\ m/s\times 16\ s$

x = 48 meters

Hence, this is the required solution.

4 0

3 years ago

You are designing an elevator for a hospital. The force exerted on a passenger by the floor of the elevator is not to exceed 1.7

HACTEHA [7]

Answer:

5.62 m/s

Explanation:

Newton's law of motion can be used to determine the maximum speed of the elevator. In the question, we are given:

Force exerted by the elevator (R) = 1.7 times the weight of the passenger (m*g)

Thus: R = 1.7*m*g

Distance (s) = 2.3 m

Newton's second law of motion: R - m*g = m*a

1.7*m*g - m*g = m*a

a = 0.7*m*g/m = 0.7*g = 0.7*9.8 = 6.86 m/s²

To determine the maximum speed:

$v^{2} _{f} = v^{2} _{i} + 2as$ $= 0 + 2(6.86)(2.3) = 31.556$

$v_{f} = \sqrt{31.556} = 5.62 m/s$

Therefore, the elevator maximum speed is equivalent to 5.62 m/s.

8 0

3 years ago

Which lists three organic biological molecules?

igor_vitrenko [27]

Answer:

Explanation:

I'm learning it in science.

8 0

3 years ago