Mary and jim find an unusual rock in their backyard. which question about the rock cannot be answered through scientific investigation 1. how old is the rock 2.what minerals make up the rock 3.is it the most unusual rock in the area 4.is it the heaviest rock in the backyard

correct answer is 3(Is it the most unusual rock in the area)

Explanation:

Option 1:

During the formation of a rock some quantity of radioactive elements mixed with it. By measuring the quantity of this radioactive element scientist can determine the age of the rock which is known as absolute age.

option 2:

Throgh scientific investigation scientist can determine the types of minerals which make up the rock

option 3:

Through scientific investigation scientist cannot determine whether the rock is the most unusual or not. It can be determine by just looking all the rock in the area.

Option 4

Through scientific investigation the weight of the rock can be determine and it can be determine whether it is the heaviest rock in the backyard.

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