You can use the displacement method or the eureka can so basically in the displacement can what you have to do is to put some water into a measuring cylinder and measure its volume before adding the irregular shaped object and then measuring the level of water which had been displaced and then eureka can you can check online
Answer:
A
B

C

D

Explanation:
Considering the first question
From the question we are told that
The spring constant is 
The potential energy is 
Generally the potential energy stored in spring is mathematically represented as 
=>
=>
=>
Considering the second question
From the question we are told that
The mass of the dart is m = 0.050 kg
Generally from the law of energy conservation

=> 
=> 
Considering the third question
The height at which the dart was fired horizontally is 
Generally from the law of energy conservation

Here KE is kinetic energy of the dart which is mathematical represented as

=> 
=> 
=> 
Considering the fourth question
Generally the total time of flight of the dart is mathematically represented as

=> 
=> 
Generally the horizontal distance from the equilibrium position to the ground is mathematically represented as

=> 
=> 
Use of lubricant
Use of ball bearers
Use of streamlined body
Use of graphite
Answer:
The answer is "
"
Explanation:

velocity of car | respect to car :
