on a planet x a man throws a 500 g mass with a speed 20m/sec and catches it as it comes down 20 sec later.the weight of the mass is? Share with your friends Share 2 Sandeep K. Gupta answered this Dear Student, Given- Mass m=500g=0.5 kg , u=20 m/sBecause mass will uder gravity of the planet hence for the given mass time taken for upwards motion will be same as time for downwards motion.So, time for upwards motion t=10 sApply equation of motion for motion under gravityv=u-gpt (for upwards motion)0=20-gp(10)gp=2 m/s2Hence weight of the bolock is given by W=mg=0.5×2= 1 N Regards. 2 View Full Answer Srikanth answered this Dear student, Use the equation...v = u+ at.. substitute the values given and find the acceleration and multiply with 0.5 kg.. and you will get the weight of the mass. so.., I hope this answer would be very helpful for you...dude... -1