1) Focal length
We can find the focal length of the mirror by using the mirror equation:

(1)
where
f is the focal length

is the distance of the object from the mirror

is the distance of the image from the mirror
In this case,

, while

(the distance of the image should be taken as negative, because the image is to the right (behind) of the mirror, so it is virtual). If we use these data inside (1), we find the focal length of the mirror:

from which we find

2) The mirror is convex: in fact, for the sign convention, a concave mirror has positive focal length while a convex mirror has negative focal length. In this case, the focal length is negative, so the mirror is convex.
3) The image is virtual, because it is behind the mirror and in fact we have taken its distance from the mirror as negative.
4) The radius of curvature of a mirror is twice its focal length, so for the mirror in our problem the radius of curvature is:
Answer:
Force constant, k = 653.3 N/m
Explanation:
It is given that,
Weight of the bag of oranges on a scale, W = 22.3 N
Let m is the mass of the bag of oranges,


m = 2.27 kg
Frequency of the oscillation of the scale, f = 2.7 Hz
We need to find the force constant (spring constant) of the spring of the scale. We know that the formula of the frequency of oscillation of the spring is given by :



k = 653.3 N/m
So, the force constant of the spring of the scale is 653.3 N/m. Hence, this is the required solution.
consider the motion of con from top to bottom
Y = vertical displacement = 1000 m
a = acceleration due to gravity = 9.8 m/s²
v₀ = initial velocity at the top = 0 m/s
v = final velocity at the bottom = ?
using the kinematics equation
v² = v²₀ + 2 aY
v² = 0² + 2 (9.8) (1000)
v = 140 m/s
t = time taken to hit the ground
Using the equation
v = v₀ + at
140 = 0 + 9.8 t
t = 14.3 sec
Answer:
beta particles
Explanation:

Given mass = 14.0 g
Molar mass = 137 g/mol

According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number
of particles.
1 mole of cesium contains atoms =
0.102 moles of cesium contains atoms =
The relation of atoms with time for radioactivbe decay is:

Where
=atoms left undecayed
= initial atoms
t = time taken for decay = 3 minutes
= half life = 30.0 years =
minutes
The fraction that decays : 
Amount of particles that decay is = 
Thus
beta particles are emitted by a 14.0-g sample of cesium-137 in three minutes.
Answer:
Because the chemical energy is converted to electrical enegy in the cell phone
Explanation:
This set up is not a voilation of the first law of thermodynamics because the chemical energy is not lost, it is only being transformed into electrical energy.
According to the first law of thermodynamics "energy is neither created nor destroyed but transformed from one form to another".
- In a charged cell phone, the chemical energy is being transformed to electrical energy as you use it.
- A phone cannot directly be powered with chemical energy.
- The energy transformation to electrical energy makes it possible to use the phone.
- In this process no energy is lost nor created. But simply, energy is transformed.