1.
Answer:
a) It is less
Explanation:
By energy conservation we can say that initial potential energy of both child must be equal to the final kinetic energy of the two child.
Since initially they are at same height so we will say that initial potential energy will be given as
and MgH
so the child with greater mass has more energy and hence smaller child will reach with smaller kinetic energy
2.
Answer:
b. The two speeds are equal.
Explanation:
As we know by mechanical energy conservation law we have
since both child starts at same height so here they both will reach the bottom at same speed
3.
Answer:
c. The two accelerations are equal
Explanation:
Since we know that average acceleration of the motion is given as
since here initial and final speeds are same so they both must have same average acceleration here.
Answer:
7350 J
Explanation:
The gravitational potential energy of the rock sitting on the edge of the cliff is given by:
where
m is the mass of the rock
g is the gravitational acceleration
h is the height of the cliff
In this problem, we have
m = 50 kg
g = 9.8 m/s^2
h = 15 m
Substituting numbers into the formula, we find:
Answer:
40 MJ (D)
Explanation:
Quantity of heat (Qh) = 100 MJ
temperature of steam (Th) = 450°c = 450 + 273 = 723 K
emperature of water (TI) = 20 °c = 20 + 273 = 293 k
efficiency = (Qh-Qi)/Qh = (Th-Ti)/Th
- Qi= 0.5947 x 
- (0.5947 x ) = Qi
Qi = 40.5 MJ equivalent to 40 MJ (D)
This question deals with the law of conservation of momentum, which basically says that the total momentum in a system must stay the same, provided there are no outside forces. Since you were given the mass and velocity of the two objects you can find the momentum (p=mv) of each and then add them together to find the total momentum of the system before they collide. This total momentum must be the same after they collide. Since you have the mass and velocity of one of the objects after the collision you can find the its momentum after. Subtract this from the the system total and you will have the momentum of the other object after the collision. Now that you know the momentum of the other object you can find its velocity using p=mv and its mass from before.
Be careful with the velocities. They are vectors, so direction matters. Typically moving to the right is positive (+) and moving to the left is negative (-). It is not clear from your question which direction the objects are moving before and after the collision.
First, you have to write what you know:
V = 3.60 m/s
D = ?
T = 18.4 s
Next, you plug everything into this formula:
V = D/T
3.60 m/s = ?/18.4 s
Then, you multiply 3.60 m/s and 18.4 s
D = 66.24 m
