Answer:
The right solution is "0.50 m/s²". A further explanation is provided below.
Explanation:
The given values are:
Mass,
m = 50 kg
Speed,
v = 10 m/s
Rolling friction acting backward (south),
f = 10 N
Air resistance acting backward (south),
= 15 N
The total force acting will be:
⇒ 
On substituting the given values, we get
⇒ 
⇒ 
Now,
⇒ 
On substituting the given values, we get
⇒ 
⇒ 
The horizontal acceleration will be "0.50 m/s²" because the (-)ve sign indicates it in south direction.
Acceleration = ms^(-1)
= 60/4
=15 ms with the power of -1
Answer:
Kinetic energy
Explanation:
Total energy of any system is always conserved.

E= Total energy
K = kinetic energy
U = Potential energy
Kinetic energy is the energy acquired by the system due to the virtue of it's motion.
Potential energy is the energy acquired by the system due to the virtue of it's configuration.
Also, Kinetic energy 


Answer: 1500 m/sec. ( b )
Solution:
V= f (λ)
Speed = frequency. Wavelength
And frequency = 1/time period
First we will find the frequency :
Frequency = 1/time period
1/0.006 = 166.67 Hz
Using this in the equation:
Speed = frequency. Wavelength
V= f (λ)
9 × 166.67
= 1500.03 ≈ 1500
V (Speed) = 1500 m/s.
Note: Do not forget to mention the units or otherwise they may cost you marks!