1. A 40 kg rock falls from rest from the top of a 64 m high tower and falls with negligible air resistance. How much kinetic energy (KE) and potential energy (PE) does the rock have when it is 28 m above the ground?
(A) KE = 0; PE = 2.5 x 104

J (B) KE = 1.1 x 104 J; PE = 1.4 x 104

J (C) KE = 1.4 x 104 J; PE = 1.1 x 104

J (D) KE = 2.5 x 104 J; PE = 0

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles

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

there are no atoms