Answer:
12
Explanation:
The equation is w= f *d
36=3*d
12=d 12 units is the mass
Answer:
Approximately (assuming that the car is moving on level ground, and that there is no friction to hinder the motion of the car.)
Explanation:
Formula for the kinetic energy, , of an object of travelling at velocity :
.
Let and denote the velocity of this car before and after the acceleration.
Kinetic energy of this car before the acceleration:
.
Kinetic energy of this car after the acceleration:
.
Assume that this car was travelling on level ground. Also assume that there is no friction to hinder the motion of this car. The work of the engine of this car would be equal to the amount of that the car has gained:
.
Answer: Density
Explanation: Recall Archimedes Principle. There are two forces acting an object submerged in a liquid: the force of gravity and the (opposite directed) force of buoyancy. The buoyancy is proportional to the mass of the liquid displaced by the submerged part of the object.
Density is the ratio of mass to volume. Therefore if the density of the submerged object is higher than that of the displaced liquid, the net force will point in the direction of the gravity (object will sink). In the opposite case, the net force will point in the direction of the buoyant force (upward) and the object will float.
Answer:
Explanation:
The wheel and falling student will have common acceleration .
For rotational motion of wheel
Tx r = I α , T is tension in the crank , α is angular acceleration of wheel , I is moment of inertia , r is radius of the wheel.
= I a / r
T = I a / r²
For motion of student
Mg - T = Ma , M is mass of the wheel.
Mg - I a / r² = Ma
Mg = Ma +I a / r²
Mg = (M +I / r²)a
a = Mg / (M +I / r²)
= 51 x 9.8 / ( 51 + 9.6 / .3² )
499.8 / (51+ 106.67 )
= 499.8 / 157.67
= 3.17 m / s².
If time t is taken to fall by 12 m
12 = 1/2 a t²
24 / a = t²
24 / 3.17 =t²
t²= 7.57
t = 2.75 s
velocity to reach sidewalk
v = u + at
= 3.17 x 2.75
= 8.72 m / s
The are called alakali earth metals.