Answer:
4m/s2
Explanation:
The following data were obtained from the question:
U (initial velocity) = 10m/s
V (final velocity) = 30m/s
t (time) = 5secs
a (acceleration) =?
Acceleration is the rate of change of velocity with time. It is represented mathematically as:
a = (V - U)/t
Now, with this equation i.e
a = (V - U)/t, we can calculate the acceleration of the race car as follow:
a = (V - U)/t
a = (30 - 10)/5
a = 20/5
a = 4m/s2
Therefore, the acceleration of the race car is 4m/s2
#1
Volume of lead = 100 cm^3
density of lead = 11.34 g/cm^3
mass of the lead piece = density * volume


so its weight in air will be given as

now the buoyant force on the lead is given by


now as we know that


so by solving it we got
V = 11.22 cm^3
(ii) this volume of water will weigh same as the buoyant force so it is 0.11 N
(iii) Buoyant force = 0.11 N
(iv)since the density of lead block is more than density of water so it will sink inside the water
#2
buoyant force on the lead block is balancing the weight of it




(ii) So this volume of mercury will weigh same as buoyant force and since block is floating here inside mercury so it is same as its weight = 11.11 N
(iii) Buoyant force = 11.11 N
(iv) since the density of lead is less than the density of mercury so it will float inside mercury
#3
Yes, if object density is less than the density of liquid then it will float otherwise it will sink inside the liquid
To solve this problem it is necessary to apply the concepts related to the magnetic dipole moment in terms of the current and the surface area, as well as the current density, as a function of the current over the area.
Part A) By definition we know that magnetic dipole moment is

Where,
I = Current
S = Area

Replacing with our values we have that,

Re-arrange to find I,

Part B) To find the Current density we need to find the cross sectional area of the Wire:

Finally the current density is simply J

PART C) Finally to make the comparison with the given values we have to cross-sectional area would be

Therefore the current density would be

Comparing the two values we can see that the 2mm wire has a higher current density.
Answer:
The vapor pressure of cyclohexane at 81.0°C is 101325 Pa.
Explanation:
Given that,
Boiling point = 81.0°C
Atmospheric pressure :
Atmospheric pressure is the force per unit area exerted by the weight of the atmosphere.
The value of atmospheric pressure is

Vapor pressure :
Vapor pressure is equal to the atmospheric pressure.
Hence, The vapor pressure of cyclohexane at 81.0°C is 101325 Pa.
Answer:
The change in momentum of the ball is 24 kg-m/s
Explanation:
It is given that,
Mass of the ball, m = 1 kg
Initial velocity of the ball, u = -12 m/s (in downwards)
Final velocity of the ball, v = +12 m/s (in upward)
We need to find the change in momentum of the ball.
Initial momentum of the ball, 
Final momentum of the ball, 
Change in momentum of the ball, 

So, the change in momentum of the ball is 24 kg-m/s. Hence, this is the required solution.