Explanation :
It is given that,
Mass of the car, m = 1000 kg
Force applied by the motor, 
The static and dynamic friction coefficient is, 
Let a is the acceleration of the car. Since, the car is in motion, the coefficient of sliding friction can be used. At equilibrium,




So, the acceleration of the car is
. Hence, this is the required solution.
Answer:

Explanation:
Given that,
Angular speed of a skater, 
The moment of inertia of the skater, I = 0.6 kg-m²
We need to find the angular momentum of the skater. The formula for the angular momentum of the skater is given by :

Substitute all the values,

So, its angular momentum is equal to
.
No,
To emit light an electron has to jump down to a lower energy level but in an electron is unable to go any lower in ground state.
Answer:
el plomo será el más largo
Explanation:
Dado que;
longitud inicial (l1) = 4m
Longitud final l2
aumento de temperatura (θ) = 10 ° C
Coeficiente de expansión lineal α
Ahora para el hierro;
α = 11,7 x 10-6
Desde;
l2-l / l1θ = α
l2 = α l1θ + l1
l2 = l1 (αθ + 1)
l2 = 4 ((11,7 x 10-6 * 10) + 1)
l2 = 4.00044 m
Para el plomo
l2 = 4 ((27,3 x 10-6 * 10) + 1)
l2 = 4,00109 m
Para cobre
l2 = 4 ((16,7 x 10-6 * 10) + 1)
l2 = 4.000668 m
Por lo tanto, el plomo será el más largo