Answer:
17.64 km/h
Explanation:
mass of car, m = 1000 kg
Kinetic energy of car, K = 1.2 x 10^4 J
Let the speed of car is v.
Use the formula for kinetic energy.
By substituting the values
v = 4.9 m/s
Now convert metre per second into km / h
We know that
1 km = 1000 m
1 h = 3600 second
So, 
v = 17.64 km/h
Thus, the reading of speedometer is 17.64 km/h.
We will convert the 1dm3 in terms of cm3 as follows:
1dm^3 = (10 cm)^3
= 1000 cm^3
The mass of platinum is equal to 900 lb.
Then we will convert the mass in terms of grams as follows:
1 lb = 453.6 g
900 = 900 x 453.6 g
= 408240 g
Then density of platinum is equal to 21.4 g/cm^3
We will calculate the volume of platinum in mass 408240 g as follows:
Volume of platinum = mass of platinum / density of platinum
= 408240 g / 21.4 g/cm^3
= 19076.6 cm^3
The total volume of platinum is 19076.6 cm^3
The volume of platinum in 1 L bar is 1000cm^3
So, to calculate the number of bars we will use the formula as follows;
Number of bars = volume of platinum available / volume of platinum required in 1 L bar
= 19076.6 cm^3 / 1000 cm^3
= 19
So, the number of bars are 19.
Time required : 3 s
<h3>Further explanation
</h3>
Power is the work done/second.
To do 33 J of work with 11 W of power
P = 11 W
W = 33 J
Answer:
Yes both = and - g can be felt by a rider in a roller coaster.
Explanation:
It is crucial to understand how we feel gravity in this case.
We humans have no sensory organs to directly detect magnitude and direction like some birds and other creatures, but then how do we we feel gravity?
When we stand on our feet we feel our weight due to the normal reaction of floor on our feet trying to keep us stand and our weight trying to crush us down. In an elevator we feel difference in our weight (difference magnitudes of gravity) but actually we are feeling the differences in normal reactions under different accelerations of the elevator.
In the case of roller coaster you will feel +g as you sit on a chair in it, but will feel -g when you are in upside down position as roller coaster move.
When you are seated you will feel the normal reaction of seat on you giving you the feeling +g and the support of the buckles to stay in the roller coaster when you are upside down will give you the -g feeling.
<u>This is just the physics approach</u>, a biological approach can be given in association with sensors relating to ears.
<span>So we want to know why is there a difference between the force of gravity on the Moon and the force of gravity of the Earth. So the gravitational force between two objects depends on the masses of both objects. That can be seen from Newtons universal law of gravity. F=G*m1*m2*(1/r^2). So lets say we are holding an object of mass m=1kg on a height r=1m on the Moon and we are holding the same object on the Earth also on the same height of r=1m. The Gravitational force on the Earth will be Fg=G*M*m*(r^2) where M is the mass of the Earth. The force between the moon and that object will be Fg=G*n*m*(r^2), where n is the mass of the moon. Since mass of the Moon is much smaller than mass of the Earth, The gravitational force between the Moon and that body will be almost 6 times smaller than the gravitational force between the Earth and that body. So the correct answer is B. </span>
