Recall formula for Kinetic energy is:
KE = 1/2mv^2, where KE = 275J
and momentum (which is 25.0 kg m/s) = m*v
Therefore substitute for KE and mv in the equation above to get speed
=> 275 = 0.5 * 25 * v
v = 275/12.5
v = 22m/s
to get mass m, recall momentum = m*v
=> 25= 22*m
m= 25/22 = 1.3663kg
