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
Answer:
1.5 m/s²
Explanation:
For the block to move, it must first overcome the static friction.
Fs = N μs
Fs = (45 N) (0.42)
Fs = 18.9 N
This is less than the 36 N applied, so the block will move. Since the block is moving, kinetic friction takes over. To find the block's acceleration, use Newton's second law:
∑F = ma
F − N μk = ma
36 N − (45 N) (0.65) = (45 N / 9.8 m/s²) a
6.75 N = 4.59 kg a
a = 1.47 m/s²
Rounded to two significant figures, the block's acceleration is 1.5 m/s².
Usually the coefficient of static friction is greater than the coefficient of kinetic friction. You might want to double check the problem statement, just to be sure.
Mass - Yes - Yes
Drop height - Yes - Yes
Initial velocity - No - No
Acceleration due to gravity - Yes - Yes
Object size - No - No
Hope this helps!
The formula used for finding the tangential speed (speed of something that is moving in a circular path) of an orbiting object is:
V₍t₎ = ωr
V₍t₎ = tangential speed or velocity
ω = angular velocity
r = radius of the circular path
if time taken t is only given then use this formula to calculate the tangential speed:
V₍t₎ = 2πr/t, t is time taken
