When the trolleys are released, it takes 0,3 s for the spring to unwind to its natural length - NSC Physical Sciences - Question 4 - 2016 - Paper 1
Question 4
When the trolleys are released, it takes 0,3 s for the spring to unwind to its natural length. Trolley Q then moves to the right at 4 m s⁻¹.
4.1 State the principle... show full transcript
Worked Solution & Example Answer:When the trolleys are released, it takes 0,3 s for the spring to unwind to its natural length - NSC Physical Sciences - Question 4 - 2016 - Paper 1
Step 1
State the principle of conservation of linear momentum in words.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The total linear momentum in a closed system remains constant before and after an event, such as a collision.
Step 2
Velocity of trolley P after the trolleys are released.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Using the conservation of momentum, we have:
mPvPi+mQvQi=mPvPf+mQvQf
Substituting in the known values:
0=(0.4)(vPf)+2.40.4vPf=−2.4vPf=−6
Thus, the velocity of trolley P after release is 6extms−1 to the left.
Step 3
Magnitude of the average force exerted by the spring on trolley Q.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Using the formula for force:
F=ma
We first need to find the acceleration of trolley Q:
Given the initial velocity vQi=0 and final velocity vQf=4 m/s, over rianglet=0.3 s:
a=ΔtvQf−vQi=0.34−0=13.33 m/s2
Now substituting into the force formula:
F=(0.6)(13.33)=8extN
Step 4
Is this an elastic collision? Only answer YES or NO.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!