Answer:
The time taken to stop the box equals 1.33 seconds.
Explanation:
Since frictional force always acts opposite to the motion of the box we can find the acceleration that the force produces using newton's second law of motion as shown below:

Given mass of box = 5.0 kg
Frictional force = 30 N
thus

Now to find the time that the box requires to stop can be calculated by first equation of kinematics
The box will stop when it's final velocity becomes zero

Here acceleration is taken as negative since it opposes the motion of the box since frictional force always opposes motion.
Answer:
k = 4422.35 KN/m
Explanation:
Given that
Frequency ,f= 29 Hz
m = 7.5 g
Natural frequency ω
ω = 2 π f
We also know that for spring mass system
ω ² m =k
k=Spring constant
So we can say that
( 2 π f)² = m k
By putting the values
(2 x π x 29)² = 7.5 x 10⁻³ k
33167.69 = 7.5 x 10⁻³ k
k=4422.35 x 10³ N/m
k = 4422.35 KN/m
Therefore spring constant will be 4422.35 KN/m
1 Kilojoule [kJ] = 737.562 149 277 27 Foot pound force [ftlbf]
If a Substance conducts heat easily then it is considered a good conductor, since the electrons can move freely within the substance.
Answer:
(e)
Explanation:
At resonance we know that 
That is 



We have given resonance frequency f =4511 Hz and inductance L=1.82 mH
So 



So option e is the correct answer