Answer:
The speed of the car is 20.84 m/s.
Explanation:
Given that,
The distance covered by the car, d = 150 km
Time, t = 7200 s
We need to find the speed of the car. We know that the speed of an object is given by total distance divided by total time taken. Mathematically,
So, the speed of the car is 20.84 m/s.
Answer:
6.7*10^8 mi/hr
Explanation:
(3*10^8 m)/1s * (3600 s)/ 1 hr * (1 mi)/ 1609 m
6.7*10^8 mi/hr
Friction is caused by two solids rubbing together quickly.
The initial mechanical energy is the potential energy (PE) which can be solved through the equation,
PE = mgh = (40 kg)(9.8 m/s²)(12 m) = 4,704 J
The energy at the bottom is the kinetic energy and can be calculated through the equation,
KE = 0.5mv² = (0.5)(40 kg)(10 m/s)² = 2000 J
Therefore, she lost 2,704 J of energy due to friction
Answer: 2.55 joules, -9.81 joules, -12.36 joules
Explanation:
the parameters given from the question are :
mass (m) = 0.20 kg
height above water (h₁) = 1.3m
depth of the well (h₂) = 5m = -5m (the negative sign is there because it is a depth below the surface )
constant value for acceleration due to gravity (g) = 9.8 m/s
- potential energy (PE) before the stone is released = m x g x h₁
PE₁ = 0.20 x 9.8 x 1.3 = 2.55 joules
- potential energy (PE) when it reaches the bottom of the well= m x g x h₂
PE₂ = 0.2 x 9.8 x (-5) = -9.81 joules
- change in potential energy = PE₂ - PE₁
= -9.81 - 2.55 = -12.36 joules