Answer:
The work done against gravity is 78.4 J
Explanation:
The work is calculated by multiplying the force by the distance that the
object moves
W = F × d, where W is the work , F is the force and d is the distance
The SI unit of work is the joule (J)
We need to find the work done against gravity when lowering a
16 kg box 0.50 m
→ F = mg
→ m = 16 kg, and g = 9.8 m/s²
Substitute these value in the rule
→ F = 16 × 9.8 = 156.8 N
→ W = F × d
→ F = 156.8 N and d = 0.50
Substitute these values in the rule
→ W = 78.4 J
<em>The work done against gravity is 78.4 J</em>
Answer:
Mass of bike = 38 kg.
Explanation:
Kinetic energy is given by the expression, 
, where m is the mass and v is the velocity.
Here speed of child riding bike = 6 m/s
Mass of child = 30 kg
Total kinetic energy = 1224 J
Let the mass of bike be, m kg
So, total mass of child and bike = (m + 30) kg
Substituting,
So, mass of bike = 38 kg.
Answer:
Explanation:
Given
Weight of Person 
Cave is 
deep
Breaking stress 
Net Force on Person
The shortest time such that the person can be taken out of cave
where
h=distance moved
t=time
a=acceleration
The wires would remain attracted to each other.
Option D.
Explanation:
It is known that magnetic flux will be generated in conductors with varying emf. So when current is flowing in two parallel conductors, the magnetic flux will be generated in those wires. If the current is flowing in same direction in both the wires, then the magnetic flux will be generated towards inside and outside the wires. Thus, the wire will get attracted to each other till the time the current is flowing in the same direction in both the wires. So if the current flow in each wire was reversed at the same time, then the wire would remain attracted to each other.
