Answer:
a)Velocity of car =v=16 m/s
b)Force against the track at point B=1.15*
N
Explanation:
Given mass of roller coaster=m=350 kg
Position of A=Ha=25 m
Position of B=Hb=12 m
Net potential energy=mg(ha-hb)
Net potential energy=(350)(9.80)(25-12)
Net potential energy=44590 J
Using energy conservation
net kinetic energy=net potential energy
(1/2)mv^2=mg(ha-hb)
m=350
velocity=v=16 m/s
b)There two force acting,centripetal force upward and gravity downward.
Thus net force acting will be
Net force=(mv^2/r)-mg
Net force=14933.33-3430
Net force=1.15*
N
Bro I really think it might be c
Answer:
Mass of the aluminium chunk = 278.51 g
Explanation:
For an isolated system as given the energy lost and gains in the system will be zero therefore sum of all transfer of energy will be zero,as the temperature will also remain same
A specific heat formula is given as
Energy Change = Mass of liquid x Specific Heat Capacity x Change in temperature
Q = m×c×ΔT
Heat gain by aluminium + heat lost by copper = 0 (1)
For Aluminium:
Q = 
Q = m x 17.94 joule
For Copper:

Q= 4996.53 Joule
from eq 1
m x 17.94 = 4996.53

Mass of the aluminium chunk = 278.51 g
The time taken by the swimmer was 1 hour.
Why?
Since the swimmer is maintaining an angle of 150° while he was swimming, there were two components of the speed (horizontal and vertical). If we want to calculate the time taken by him to cross the river, we need to calculate the vertical speed and consider that the flow's speed is compensated by his horizontal speed.
We can calculate both components of the speed using the following formula:

Now, calculating we have:

Therefore, we have that the horizontal speed is compesating the flow's speed while his vertical speed is used to cross the river which is 1 Km wide.
Hence, we have that the tame taken is:

Have a nice day!
Force is calculated F=m×a.
If both ships speed up with the same force, but have a different mass, This means that a also has to be different. If F is the same but ship a has a bigger mass(m) than ship b, then the acceleration(a) of ship b has to be bigger so F of each ship is the same. So the ship with the smaller mass will speed up faster.