Question

In a new system of units called star units, 1kg* = 10 kg ; 1m* =1km and 1s*= 1 minute, what will be the value of 1 joule of energy in the new system?

Answer 1

joule is the unit of work
work=force*displacement
work=mass*acceleration*displacement
work=mass*displacement*displacement/time*time
work=mass*displacement^2/time^2
work=10kg*(1km)^2/(1 minute)^2

Answer 2

1 kg* = 10kg

1 m* = 1 km

1 s* = 1 min.

1 kg* = 1/10kg*

1 Joule = 1 kg m^2 s^-2

1/10 kg* (1/1000m*)^2 (1/60s*)^-2

= 1/10 × 1/1000 × 1/1000 × 1/(60×60)^-2 kg* m*^2 s*^-2

= 1/10^7 × (3600)^2 kg* m* s*