An equal and opposite force acting upwards
Answer: a graduated cylinder and balance
A rock has an irregular shape. so, it would be difficult to measure using a meter stick. most convenient method to find the volume would be using a graduated cylinder. we can take a fixed volume of water in the cylinder. then drop rock into it. note the new raised volume. Subtract the initial volume from final to find the volume of rock.
Using balance, mass of the rock can be measured.
we can calculate the density using the following formula:

Therefore, we need only two tools, a graduated cylinder and a balance to measure mass, volume and density of a rock.
C. Gravity acts on all objects in the universe!
Answer:
The spring stretched by x = 13.7 cm
Explanation:
Given data
Mass = 3 kg
k = 120 
Angle
= 34°
From the free body diagram
Force acting on the box = mg sin
⇒ F = 3 × 9.81 × 
⇒ F = 16.45 N ------- (1)
Since box is attached with the spring so a spring force also acts on the box.
= k x
= 120
-------- (2)
The net force acting on the body is given by
Since acceleration of the box is zero so



Put the values from equation (1) & (2) we get
16.45 = 120
x = 0.137 m
x = 13.7 cm
Therefore the spring stretched by x = 13.7 cm
When a force applied to a breaker bar the torque can be calculated by multiplying the<u> length of the lever</u> by the tangential component of force on the lever.
<h3>What is torque?</h3>
Torque is the <u>rotating equivalent</u> of force in physics and mechanics. Depending on the subject of study, it is also known as the moment, moment of force, rotating force, or turning effect. It illustrates how a force can cause a change in the body's rotational motion.
Torque is given by the formula :
α = r x F ( bold letters represent vector quantities)
The S.I. unit for torque is : N - m ( Newton - meter)
<h3>How do we define 1 N-m of torque?</h3>
The newton-metre is a torque unit (also known as a moment) in the SI system. The torque produced by a one newton force applied <u>perpendicularly to the end of a one metre long</u> moment arm is known as a newton-metre.
To learn more about torque:
brainly.com/question/14970645
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