Question

An impulse of 15 Ns acts on a 0.2 kg ball initially at rest. What is the change in momentum?

momentum =mV

how do I get to V I am given m=0.2kg

F=ma
15=0.2a
a=75m/s

do I need to time t next?

i'm so lost :(

Answer 1

15 Ns ... a 15 N force acting for one second
... or a 30 n force acting for half a second
... the net result is the same

a = f / m ... a = 15n / .2 kg = 75 m/s^2
... for one second
... the resulting velocity is 75 m/s

Answer 2

trick question
impulse IS change of momentum
F = dP / dt = d/dt (m v) = m dv/dt = m a
F dt = dP = d (m v)
here
F dt = 15 Newtons * seconds which IS dP the change in momentum

Answer 3

what is dP?
this chapter in my book doesn't use the letter d?

15=0.2v
v=75?

Answer 4

75 m/s is the speed....so the momentum is the 15N?? or 15kgm/s??

Answer 5

P is the usual notation in physics for momentum, m v
d P is change in momentum

Force, F = change in momentum d P over change in time d t

Answer 6

the momentum is 15 kg m/s
which is the same as 15 N s

Force is rate of change of momentum