Question

A vehicle of mass 10 quintals climbs up a hill 200 m high and then moves on a level road with a velocity of 36 km/hr. Calculate its total mechanical energy while running on the hilltop​

Answer 1

Answer:

2050kJ

Explanation:

v = 36km/hr = 10m/s

m = 10 quintals = 1000 kg

h = 200m

g = 10 m/s²

Mechanical energy = Kinetic energy + Potential energy

= 1/2 mv² + mgh

= 1/2×1000×10×10 + 1000×10×200

=50,000 + 20,00,000

=20,50,000J

=2050kJ

Answer 2

Given :

Mass (m) = 10 quintals = 10 × 100 = 1000 Kg

Height (h) = 200 m

Velocity = 36 Km/hr = 36×$\frac{5}{18}$ = 10 m/sec

To Find :

Total Mechanical Energy

Solution :

Potential Energy (PE) = mgh

where, m = mass; g = acceleration due to gravity; h = Height

Potential Energy (PE) = 1000 × 10 × 200

                                   =  2 × 10⁶ J

Kinetic Energy (KE) = $\frac{1}{2}$ × m × v²

where, m = mass; v = velocity

Kinetic Energy (KE) = $\frac{1}{2}$ × 1000 × (10)²

                                =  5 × 10⁴ J

∴ Total Kinetic Energy = Potential Energy + Kinetic Energy

                                     =  2 × 10⁶  +  5 × 10⁴

                                     = 205 × 10⁴  J

Therefore, the total mechanical energy is 205 × 10⁴ J or 2.05 × 10⁶ J