Answer:
plug it into your calculator
Explanation:
Kinetic energy = KE = Joules = J
KE= 1/2mv^2
90,000 = 1/2 m (12^2)
180,000 = m (144)
m = 180,000 / 144
Answer:
1960 J
Explanation:
EK = (18 kg + 62 kg)
/2 = 1960 J
That's true, you can't get any more precise than what's measured to the least precision.
First, let's list everything we have...
a = 1.83 m/s^2
F = 1870 N (converted from kN to N)
vi = 0 m/s (it says started from rest, therefore velocity starts at 0)
t = 16 s
1). "Force acting on the car" is a bit ambiguous because there are many forces. But I'm going to assume that they are looking for just a basic implementation of force equation:

where:
F = force
m = mass
a = acceleration
2). I recommend memorizing your equations of motion, because once you know them this part is also just as easy:

where:
vf = final velocity
vi = initial velocity
a = acceleration
t = time