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 :(
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
75 m/s is the speed....so the momentum is the 15N?? or 15kgm/s??
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
what is dP?
this chapter in my book doesn't use the letter d?
15=0.2v
v=75?
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
the momentum is 15 kg m/s
which is the same as 15 N s
Force is rate of change of momentum
No, you don't need to consider time (t) in this case. The change in momentum can be determined using the formula:
Change in momentum (Δp) = Final momentum (pf) - Initial momentum (pi)
But first, we need to calculate the initial and final velocities of the ball.
The formula for momentum is given by:
Momentum (p) = mass (m) × velocity (V)
Given that the mass (m) of the ball is 0.2 kg, we can rearrange the formula to solve for velocity (V):
V = p / m
Now, let's calculate the initial velocity (Vi):
Since the ball is initially at rest, the initial momentum (pi) is 0. Therefore, the initial velocity (Vi) is also 0.
Next, let's calculate the final velocity (Vf):
To do this, we need to use the impulse-momentum theorem, which states that impulse (J) is equal to the change in momentum (Δp):
Impulse (J) = Δp = F × t
Given that the impulse (J) is 15 Ns and the mass (m) is 0.2 kg, we can rearrange the formula to solve for the change in momentum (Δp):
Δp = J = F × t
Now, substitute the values we have:
15 Ns = F × t
Now, we know that impulse (J) is also equal to the force (F) multiplied by the time (t). However, for this specific problem, we are given the impulse (15 Ns) but not the time (t). Therefore, it is impossible to determine the final velocity (Vf) accurately.
Hence, without knowing the time (t) in this case, we cannot calculate the final velocity or the change in momentum.