Planets orbit the sun in the paths which are known as elliptical orbit. Each planet has its own orbit around the sun and direction in which all the planets orbit around the sun are the same. These orbits were well explained by the astronomer Kepler. The gravity of the Sun keeps the planets in their orbits. They stay in their orbits because there is no other force in the Solar System which can stop them.
Answer:
C
Explanation:
Because *censored*. Then the element *censored* your answer
Answer:
C 0.85 j/g*k
Explanation:
The specific heat capacity of a material is given by:

where
Q is the amount of heat supplied to the object
m is the mass of the object
is the increase in temperature of the object
For the object in this problem, we have
m = 117 g is the mass
Q = 1200 J is the heat supplied
is the increase in temperature
Substituting into the formula, we find the specific heat:

Answer:
A concave mirror has a radius of curvature of 20 cm. What is it's focal length? If an object is placed 15 cm in front of it, where would the image be formed? What is it's magnification?
The focal length is of 10 cm, object distance is 30 cm and magnification is -2.
Explanation:
Given:
A concave mirror:
Radius of curvature of the mirror, as C = 20 cm
Object distance in-front of the mirror = 15 cm
a.
Focal length:
Focal length is half of the radius of curvature.
Focal length of the mirror =
= 10 cm
According to the sign convention we will put the mirror on (0,0) point, of the Cartesian coordinate open towards the negative x-axis.
Object and the focal length are also on the negative x-axis where focal length and image distance will be negative numerically.
b.
We have to find the object distance:
Formula to be use:
⇒ 
⇒ Plugging the values.
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
Image will be formed towards negative x-axis 30 cm away from the pole.
c.
Magnification (m) is the negative ratio of mage distance and object distance:
⇒ 
⇒ 
⇒ 
The focal length of the concave mirror, is of 10 cm, object distance is 30 cm and magnification is -2.
Answer:
t = 1.09 s.
Explanation:
This is a one-dimensional kinematics question, so the equations of kinematics will be sufficient to solve the question.

This quadratic equation can be solved using determinant.

Of course, we will choose the positive time.