Answer:
finding Cepheid variable and measuring their periods.
Explanation:
This method is called finding Cepheid variable and measuring their periods.
Cepheid variable is actually a type of star that has a radial pulsation having a varying brightness and diameter. This change in brightness is very well defined having a period and amplitude.
A potent clear link between the luminosity and pulsation period of a Cepheid variable developed Cepheids as an important determinants of cosmic criteria for scaling galactic and extra galactic distances. Henrietta Swan Leavitt revealed this robust feature of conventional Cepheid in 1908 after observing thousands of variable stars in the Magellanic Clouds. This in fact turn, by making comparisons its established luminosity to its measured brightness, allows one to evaluate the distance to the star.
Answer:
b. -1.5 m/s²
Explanation:
Given the following data;
Initial velocity = 15m/s
Time = 10 seconds.
Since the car came to rest, final velocity = 0m/s
To find acceleration;
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of final speed from the initial speed all over time.
Mathematically, acceleration is given by the equation;
Where,
a is acceleration measured in 
v and u is initial and final speed respectively, measured in 
t is time measured in seconds.
Substituting into the equation, we have;
Acceleration = -1.5 m/s²
Net force can be defined as the sum of force acting on an object in all the directions
.i.e Net force= F acting on a body at upward direction+ F at downward direction+ F at leftward direction+ F at rightward direction.
e.g if a body is at rest the sum of forces acting on body in all direction is zero
but if a body is moving its mean body is facing an unbalanced net force.
Explanation:
6. Converge or come together
7. convex
