In order to calculate velocity, we'd need to know the straight-line distance between the start and the finish, and we'd also need the direction of that line. The best we can do with the information given in the question is calculate the average SPEED.
Average speed = (total distance covered) / (time to cover the distance).
Distance covered in the first 2 hours = (2 hr) x (40 km/hr) = 80 km.
Distance covered in the second 2 hours = (2 hr) x (60 km/hr) = 120 km.
Total distance covered = (80 + 120) = 200 km
Time to cover the distance = (2 + 2) = 4 hours
Average speed = (200 km) / (4 hours) = 50 km/hour
Answer=Density
D=m/v (the mass in a given volume is the density)
Final velocity = initial velocity + (acceleration*time)
That is v = u + at
So 20 = u + (2.15*7)
20 = u + 15.05
Thus, u = 20 - 15.05
= 4.95 meters/second
that is C
Answer:
c. Kinetic energy
Explanation:
The two types of energy involved in this problem are:
- Potential energy: it is the energy possessed by an object due to its position. It is calculated as

where
m is the mass of the object
g is the acceleration due to gravity
h is the height of the object relative to the ground
From the formula, we see that the higher the object is above the ground (higher h), the larger the potential energy of the object. In this problem, the pig is falling down, so the value of h is decreasing, therefore the potential energy is decreasing as well.
- Kinetic energy: it is the energy possessed by an object due to its motion. It is given by:

where
m is the mass of the object
v is its speed
In this problem, as the pig falls down, it accelerates, so its speed increases: since the kinetic energy is proportional to the square of the speed, as the speed increases, its kinetic energy increases too. So, the correct answer is
c. Kinetic energy