Answer:

Explanation:
The period of a simple pendulum is given by the equation

where
L is the lenght of the pendulum
g is the acceleration due to gravity at the location of the pendulum
We notice from the formula that the period of a pendulum does not depend on the mass of the system
In this problem:
-The pendulum comes back to the point of release exactly 2.4 seconds after the release. --> this means that the period of the pendulum is
T = 2.4 s
- The length of the pendulum is
L = 1.3 m
Re-arranging the equation for g, we can find the acceleration due to gravity on the planet:

Answer:
C. 8,000 N
Explanation:
<em>Newton's second law of motion</em> describes the relationship between an object's mass and the amount of force needed to accelerate it.
This law can be expresses as F=ma,
where
- F - force acting on an object
- m- the mass of an object
- a - its acceleration
The more mass an object has, the more force you need to accelerate it. And the greater the force, the greater the object's acceleration.
<em>F = ma </em>
<em> =2000×4 = 8,000 N</em>
Answer:
Mass, m = 20000 kg
Explanation:
The force acting on the shark, 
Acceleration of the shark, a = 1.25 m/s²
We need to find the mass of the Shark. The force acting on an object is given by :
F = ma
m is the shark's mass
So,

So, the mass of the Shark is 20000 kg.
Answer:
Efficiency
Explanation:
- The amount of mechanical work an engine can do per unit of heat energy it uses is called its efficiency.
- It is also defined as the output divided by the total electrical power consumed.
- In terms of heat, efficiency of engine is given by :

are output heat and input heat respectively.
Hence, the correct option is (d) "efficiency"