Answer: Tension = 53.6N
Explanation:
Given that
Height h = 1 m
Time t = 1.7 s.
Mass m = 5.1 kg
From the equation of the motion we can get the acceleration of the elevator:
h = X0+ V0t + at2/2;
Th elevator starts from rest with a constant upward acceleration. Initial velocity Vo = 0, also Xo = 0; thus
a = 2h/t2 = 2 × 1/1.7^2
a = 0.69 m/s2.
Then we can find the tension in the cord by using the formula
T = mg + ma
= 5.1 (9.8 + 0.69)
= 5.1 × 10.5
= 53.6N
Answer:
Explanation:
doubling the speed will have a greater impact on kinetic energy as KE is a product of mass and the square of velocity.
KE = ½mv²
Base KE = ½(0.005)2.0² = 0.01 J
doubling the mass
KE = ½(0.010)2.0² = 0.02 J
doubling the velocity
KE = ½(0.005)4.0² = 0.04 J
Observations is the answer.
Answer:
(a) 
(b) 
(c) 
Explanation:
(a) The total mechanical energy of the system is conserved.

(b) The conservation of energy states

(c) As explained in part (a) the total mechanical energy of the system is equal to the initial kinetic energy, since the potential energy of the system at that point is zero.

Kinetic energy = (1/2) (mass) (speed)²
Before slowing down, the car's speed is 25 m/s,
and its kinetic energy is ...
(1/2) (1,500 kg) (25 m/s)²
= (1/2) (1,500 kg) (625 m²/s²)
= 468,750 joules .
After slowing down, the car's speed is 15 m/s,
and its kinetic energy is ...
(1/2) (1,500 kg) (15 m/s)²
= (1/2) (1,500 kg) (225 m²/s²)
= 168,750 joules.
The car lost (468,750 - 168,750) = 300,000 joules of K.E.
The law of Conservation of Energy says:
That 300,000 joules had to go somewhere.
If it's a standard, gas-powered car, then the kinetic energy got
put into the brakes. The energy turned into heat, and the heat
was carried off in the air.
If it's a more modern electric or hybrid car, then the kinetic energy
spun the wheel motors, turning them temporarily into electrical
generators. The generators converted the kinetic energy into
electrical energy, which got put back into the car's batteries, and
could be used again. That's why electric cars use less gas.