Water boiling is an example of a physical change. The rest are chemical changes.
Hope that helps!!
Solution :
Given :
Mass attached to the spring = 4 kg
Mass dropped = 6 kg
Force constant = 100 N/m
Initial amplitude = 2 m
Therefore,
a). 
= 10 m/s
Final velocity, v at equilibrium position, v = 5 m/s
Now, 
A' = amplitude = 1.4142 m
b). 
m' = 2m
Hence, 
c). 
Therefore, factor
Thus, the energy will change half times as the result of the collision.
Answer:
Explanation:
Far point = 17 cm . That means he can not see beyond this distance .
He wants to see at an object at 65 cm away . That means object placed at 65 has image at 17 cm by concave lens . Using lens formula
1 / v - 1 / u = 1 / f
1 / - 17 - 1 / - 65 = 1 / f
= 1 / 65 - 1 / 17
= - .0434 = 1 / f
power = - 100 / f
= - 100 x .0434
= - 4.34 D .
Answer: - 25.2 kgm/s
Explanation: The mass of the ball is 0.5kg, and the initial velocity = 10.6m/s.
The final velocity is in opposite direction of the initial hence final velocity (v) = - 19.9 m/s
Impulse = change in momentum = final momentum - initial momentum.
Final momentum = mass × final velocity
Final momentum = - 19.9 × 0.5
Final momentum = - 9.95 kgm/s
Initial momentum = mass × initial velocity
Initial momentum = 0.5 × 10.6 = 5.3kgm/s
Change in momentum = final momentum - initial momentum = - 19.9 - 5.3
Change in momentum = - 25.2 kgm/s
The negative sign implies that the change in momentum is the opposite direction relative to the first.
You start by writing down your parameters;
u=60m/s
v=0
t=8s
So acceleration(a)=v-u/t
=0-60/8
=-60/8
=-7.5m/s
To the nearest hundredth will be
-7.5*100
=-750m/s
