There is 4000 balls in the earth of the world why is that so hard for you
There are different types of contact forces like normal Force, spring force, applied force and tension force.
Answer:
18 m
Explanation:
E = mgh
45 J = (0.25 kg) (9.8 m/s²) h
h = 18 m
Answer:
v = 26.52 m/s
Explanation:
Here we know that as she passes the flag she will gain some speed
so here we can say that
Work done by all forces = change in kinetic energy of the system
so we will have

here we know that



h = 39.78 m
d = 27.81 m
so we have



M = mass of the ball A = 5.0 kg
m = mass of the ball B = ?
V = initial velocity of the ball A before collision = 20 m/s
v = initial velocity of the ball B before collision = 10 m/s
V' = final velocity of the ball A after collision = 10 m/s
v' = final velocity of the ball B after collision = 15 m/s
using conservation of momentum
M V + m v = M V' + m v'
(5.0) (20) + m (10) = (5.0) (10) + m (15)
100 + 10 m= 50 + 15 m
5 m = 50
m= 10 m/s