)a rock is suspended from a scale reads 20.0 n. a beaker of water (having a density of 1000 kg/m3) is raised up so the rock is totally submerged in the water. the scale now reads . what is the density of the rock? a) 2.50 × 103 kg/m3 b) 1.60 × 103 kg/m3 c) 2.33 × 103 kg/m3 d) 2.67 × 103 kg/m3 e) 3.00 × 103 kg/m3

The density of the rock is

(D) is correct option.

Explanation:

Given that,

Force = 20.0 N

Density = 1000 kg/m³

Suppose the scale new reads 12.5 N

We need to calculate the mass of rock

Using formula of force

Put the value into the formula

Scale reads 12.5 N after rock is totally submerged so mass of rock after submerged

We need to calculate the mass of rock

Using formula of force

Put the value into the formula

The scale reads 12.5 N = 1.25 kg so it is displacing 0.75 kg of water

We need to calculate the volume of rock using volume of water it displaces:

Using formula of volume

We need to calculate the density of the rock

Using formula of density

Put the value into the formula

Hence, The density of the rock is

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

the answer to this is proletariats.

hope this : )