A mass of 630g is hung on a spring. Using Force = mass x gravity, what is the force of the mass, acting on the spring?

6.174N or roughly 6.2N

Explanation:

630g=0.63kg

F=m*g=0.63*9.8=6.174N

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s

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