Motion & Conversions
Define Units? Difference b/w Fundamental and Derived Units(Any 2 differences)
Units are standard quantities used to express and measure physical properties (like length, mass, or time).
Difference any 2
a)What is "g" and what is its Constant Value?
b)Which of the correct SI unit and symbol for Weight?
a) "g" represents the acceleration due to gravity.
Constant value is 9.8m/s2
b) SI unit - Newton(N),
What are the formula and SI units of Work and Power?
Formula and SI units of Work:
Work= Force x displacement(distance) & Joules
Formula and SI units of Power:
Power = Work/ time and Watts or Joules/seconds
Define momentum (formula and words)
Which formula represents momentum?
Momentum means mass is motion. Any moving object has momentum
p = m v (vector).
Define "wavelength" and "frequency" in one sentence each.
Wavelength: distance between two successive identical points on wave (e.g., crest to crest).
Frequency: number of cycles per second (Hz)
What is the average acceleration of a race car that starts at rest and accelerates to 95 m/s in 13.9 seconds?
a= change in velocity/ change in time
a=95-0 / 13.9
a=6.83 m/s2
What is the type force generated perpendicular to a surface?
Normal force
a) Nia pulls a rope with 55 N and it moves 15 cm. How much work (J) did she do?
b) A light bulb uses 270,000 J of energy in 1 hour. The power of the light bulb is?(Hint: Convert time into seconds)
a) Work = 55 N × 0.15 m = 8.25 J.
b) Power is calculated using:
P = Energy(Work) / time
270,000 / 3600 s =75 W
Difference between Inertia and Momentum?
Inertia depends upon Mass only
Momentum depends upon Mass and Speed
A student triples the distance (3x) between two charged particles. The electric force will decrease to what fraction of its original value?
The electric force decreases to one-ninth (1/9) of its original value.
Convert 9.27 millimeters to meters. show work also
Answer: 0.00927 m or 9.27 x 10-3
If a 227 kg object is accelerating at 3.50 m/s², what is the net force acting on it? Show numeric answer in N.
F=794.5N
A 600 N person runs up stairs 2.50 m high in 3 s. How much power (W) did they generate? (Use correct SI.)
(hint: Calculate work first and then calculate power)
Formula of Power = Work/time Step 1: W=600×2.5=1500 J.
Step 2: P=1500/3=500 Watts
Write the equations to calculate Impulse and change in momentum?
What are the types of Waves? Also give 2 difference between them?
Types of Waves:
Mechanical Waves and Electromagnetic Waves
Difference:
1.Mechanical waves Require a medium to travel but electromagnetic waves can travel in vacuum without medium
2. Example of Mechanical waves are: Sound, water waves, seismic waves
Examples of Electromagnetic Waves are Light, X-rays, microwaves, radio waves
A car slows from 38 m/s at a rate of 3.2 m/s² for 4 s. Calculate its final velocity.
vf = vi + (a)(t) = 38 + (-3.2)(4) = 25.2 m/s
a) What is the formula for Newton’s Law of Universal Gravitation?
b) What is the constant value for "G"
a) F = G × (m₁ x m₂) / r2
b) G = 6.67×10-11N.m2/kg2
A container with a mass of 5 kg is lifted to a height of 800 cm; approximately how much work is done?
(hint: Use formula GPE)
GPE= mgh
(m=5kg, h=8m , g= 9.8)
W=5×9.8×8=392 J
Give any 3 difference b/w elastic and inelastic collision.
1. In elastic collision, Both momentum and kinetic energy are conserved but in inelastic only Momentum is conserved.
2. Objects usually bounce apart after collision in elastic collision and in Inelastic collision objects may stick together or move separately with less energy.
3. No energy is lost as heat or sound in elastic collision but Some energy is lost as heat, sound, or deformation in elastic collision.
A wave has wavelength 12.8 m with frequency 51.2 Hz. compute wave speed (show numeric).
Wave Speed =
wavelength x frequency (ν=λf)
12.8 x 51.2 = 6.5536 m/s.
Mila walks 1.2 km north, 0.4 km west, then 1.2 km south.
a)Convert distances to meters and find:
(b) total distance,
(c) displacement magnitude (meters).
a)Distances in m: 1200, 400, 1200;
b)total distance = 2800 m.
c) Displacement: north net = 0. (1.2 km north then 1.2 km south cancel) so displacement = 400 m west → 400 m.
If two sugar grains each acquire a charge of 3.0x10-11 C at a separation of 8.0x10-5 m, with what force do they repel each other?
Answer: q1=q2=3.0×10−11 C
F=1.27×10−3 N
a) What is the formula to calculate KE?
b)What is the formula of GPE?
c) How many joules of kinetic energy does a 1.3 kg book have when it is tossed across the room at 2 m/s?
a) KE: 1/2mv2
b) GPE= mgh
c) 2.6J
A 2.0 kg object moves right at 4.0 m/s and collides head-on with a 3.0 kg object moving left at 4.0 m/s. Compute total momentum before collision (include sign).
(show all work on board in 2 mins)
p1= momentum of object 1= 8.0kg.m/s
p2= momentum of object 2= -12 kg.m/s
ptotal=p1+p2
ptotal=8.0+(−12.0)
ptotal=−4.0 kg.m/s
Final Answer:
−4.0 kg.m/s
A heavy-duty motor draws 15.5 A of current when connected to a power source. If the resistance of the motor windings is 7.2 Ω, what is the supply voltage?
Use Ohm's Law: V= IR
V=(15.5)(7.2) = 111.6 V