If my math is correct your answer should be 3.0 but correct me if I'm wrong
Answer:
t = 180 / 1.4 = 129 sec (time to swim horizontally across river)
S = 129 sec * V where V is speed of current and S is the distance he will be carried downstream
The problem does not specify V the speed of the river
#21
- initial velocity=u=5m/s
- Time=t=2s
- Acceleration=a=1.3m/s²
According to first equation of kinematics
- v=u+at
- v=5+1.3(2)
- v=5+2.6
- v=7.6m/s
#22
#a
- v1=2+3(3)=2+9=11m/s
- v2=-8-4(3)=-20m/s
- v3=1-5(3)=-14m/s
The order is
#b
for speed find absolute velocity
- S1=|11|=11m/s
- S2=|-20|=20m/s
- S3=|-14|=14m/s
So order is
S1<S3<S2
Answer:
10000N
Explanation:
Given parameters:
Mass of the car = 1000kg
Acceleration = 3m/s²
g = 10m/s²
Unknown:
Weight of the car = ?
Solution:
To solve this problem we must understand that weight is the vertical gravitational force that acts on a body.
Weight = mass x acceleration due to gravity
So;
Weight = 1000 x 10 = 10000N
Given Information:
Mass of electron = m = 9x10⁻³¹ kg
initial speed of electron = v₁ = 0.92c
Force = F = 1.4x10⁻¹³ J
Distance = d = 3 m
Required Information:
Final speed of electron = v₂ = ?
Answer:
Final speed of electron = v₂ = 2.974x10⁸ m/s
Explanation:
As we know from the conservation of energy,
E₂ - E₁ = W
E₂ = E₁ + W
Where E₂ is the final energy of electron and E₁ is the initial energy of electron
The above equation can be written in the form of particle energy
γ₂mc² = γ₁mc² + W
where γ₁ and γ₂ are given by
γ₁ = 1/√1 - (v₁/c)²
γ₂ = 1/√1 - (v₂/c)²
First calculate γ₁
γ₁ = 1/√1 - (0.92c/c)²
γ₁ = 2.55 m
Now calculate γ₂
γ₂ = (γ₁mc² + W)/mc²
First we need to find the work done
W = F*d
W = 1.4x10⁻¹³*3
W = 4.2x10⁻¹³ J
so γ₂ is
γ₂ = (2.55*9x10⁻³¹*(3x10⁸)² + 4.2x10⁻¹³)/9x10⁻³¹*(3x10⁸)²
γ₂ = 7.73
Now we can find the new speed of the electron
γ₂ = 1/√1 - (v₂/c)²
Re-arranging the above equation results in
v₂ = c*√(1 - 1/γ₂²)
v₂ = 3x10⁸*√(1 - 1/7.73²)
v₂ = 2.974x10⁸ m/s