I need help on this I don’t understand

What does the term discrediting mean?

Aprojectile is launched horizontally 10m above the ground and with an initial velocity of 15 m/s. a) determine the magnitude and direction of projectile velocity at t= 1.3s b) determine the magnitude and direction of projectile acceleration at t=1.3s

Aforce of 240.0 n causes an object to accelerate at 3.2 m/s2. what is the mass of the object?