Efficiency = (energy that does the job) / (total energy used)
= (45 J) / (120J)
I think you can handle the division.
Answer:
Kinetic energy of bigger rock will be more than that of smaller one.
Explanation:
Kinetic energy of the rock is given by,
Kinetic energy = 
As velocity of both the rocks are same. Thus, kinetic energy is directly proportional to the mass of the rock
Kinetic energy ∝ mass
So, For greater mass kinetic energy will be greater and for smaller mass kinetic energy will be smaller.
Hence, Kinetic energy of bigger rock will be more than that of smaller one.
No one can really tell exactly how old the universe is. However, scientists have attempted to estimate the time by using the concept of Doppler effect which depends on the frequency of the stars and their relative velocities. From literature, the universe is about 13.82 billion years old. Thus, the age of the universe is 13.82×10⁹ times longer than a year.
Answer:
Yes
Explanation:
The plank (also called a front hold, hover, or abdominal bridge) is an isometric core strength exercise that involves maintaining a position similar to a push-up for the maximum possible time
Answer: The SI unit
Explanation: The SI units are used to describe the distance an object moves