Answer:
960 m
Explanation:
Given that,
- Speed = 120 m/s
- Time taken = 4 minutes
We have to find the distance covered.
Firstly, let's convert time in seconds.
→ 1 minute = 60 seconds
→ 4 minutes = (4 × 60) seconds
→ 4 minutes = 240 seconds
Now, we know that,
→ Distance = Speed × Time
→ Distance = (4 × 240) m
→ Distance = 960 m
Therefore, distance covered is 960 m.
Answer:
time required after impact for a puck is 2.18 seconds
Explanation:
given data
mass = 30 g = 0.03 kg
diameter = 100 mm = 0.1 m
thick = 0.1 mm = 1 ×
m
dynamic viscosity = 1.75 ×
Ns/m²
air temperature = 15°C
to find out
time required after impact for a puck to lose 10%
solution
we know velocity varies here 0 to v
we consider here initial velocity = v
so final velocity = 0.9v
so change in velocity is du = v
and clearance dy = h
and shear stress acting on surface is here express as
= µ 
so
= µ
............1
put here value
= 1.75×
× 
= 0.175 v
and
area between air and puck is given by
Area =
area =
area = 7.85 ×
m²
so
force on puck is express as
Force = × area
force = 0.175 v × 7.85 × 
force = 1.374 ×
v
and now apply newton second law
force = mass × acceleration
- force = 
- 1.374 ×
v = 
t = 
time = 2.18
so time required after impact for a puck is 2.18 seconds
Answer:
B) I1 = 1680 kg.m^2 I2 = 1120 kg.m^2
C) V = 0.84m/s T = 29.92s
D) ω2 = 0.315 rad/s
Explanation:
The moment of inertia when they are standing on the edge:
where M is the mass of the merry-go-round.
I1 = 1680 kg.m^2
The moment of inertia when they are standing half way to the center:

I2 = 1120 kg.m^2
The tangencial velocity is given by:
V = ω1*R = 0.84m/s
Period of rotation:
T = 2π / ω1 = 29.92s
Assuming that there is no friction and their parents are not pushing anymore, we can use conservation of the angular momentum to calculate the new angular velocity:
I1*ω1 = I2*ω2 Solving for ω2:
ω2 = I1*ω1 / I2 = 0.315 rad/s
Answer:V=Aq=KQr
Explanation:
Không biết V bạn kí hiệu ở đây là gì nhỉ? Có phải là điện thế?
Điện thế tại 1 điểm trong điện trường được định nghĩa là công làm vật dịch chuyển từ vị trí đó đến vô cùng. V = A/q
Chứng minh thì được, nhưng chỉ e bạn không có hiểu biết về nguyên hàm, tích phân nên không hiểu.
- Xét tại vị trí cách điện tích Q một đoạn x, khi đó điện tích q sẽ chịu 1 lực: dF=KQ.qx2
Điện tích q dịch chuyển 1 khoảng dx rất nhỏ. Khi đó công do lực điện trường gây ra là:
dA=dF.dx=KQ.qx2dx
Công để dịch chuyển điện tích q từ vị trí r đến vô cùng là:
A=∫∞rdA=∫∞rKQ.qx2dx=KQ.qr−KQ.q∞=KQ.qr
Theo đúng định nghĩa: V=Aq=KQr
Answer:
The stored energy is 140.7 watt.
The thermal energy is 62.7 watt.
The delivered energy is 203.4 watt.
Explanation:
Given that,
Inductance = 2.8 H
Resistance = 12 Ω
Potential 
Time = 0.086 s
(a). We need to calculate the energy stored in the magnetic field
Using formula of current

Using formula of energy

On differentiating


Again differentiating


Put the value into the formula


(b). We need to calculate the thermal energy
Using formula of thermal energy


Put the value into the formula


(c). We need to calculate the delivered energy by the battery
Using formula of energy



Hence, The stored energy is 140.7 watt.
The thermal energy is 62.7 watt.
The delivered energy is 203.4 watt.