Question

A worker drops his hammer off the roof of a house. The hammer has a mass of 9 kg, and gravity accelerates it at the usual 9.8 m/s2. How much force does the earth apply to the hammer

Answer 1

$\LARGE{ \underline{\underline{ \sf{Required \: answer:}}}}$

GiveN:

• Mass of the hammer = 9 kg
• Accleration due to gravity = 9.8 m/s²

To FinD:

• The force applied by earth to the hammer?

Step-by-Step Explanation:

According to Newton's second law of motion, Force is the product of mass and accleration. And we know that weight is the force with which the body is attracted towards the earth.

Here the accleration is the accleration due to gravity because the force acting is Gravitational force. Then,

⇒ F = m × g

⇒ F = 9 kg × 9.8 m/s²

⇒ F = 88.2 kg m/s²

The unit kg m/s² can also be written as N.

Hence the required force of gravity with which the hammer is attracted towards the earth is 88.2 kg m/s². Hope there was no one standing under the roof! :D

Answer 2

Question :

A worker drops his hammer off the roof of a house.The hammer has a mass of 9 kg and gravity accelerates it at the usual 9.8 m/s². How much force does the earth apply to the hammer?

Answer :

• To find force applied by earth

We know to find force by Newton's 2nd law of motion that,

${\underline{\boxed{\bf{force = mass \times gravity}}}}$

${\underline{\boxed{\bf{f = m \times g}}}}$

Given :

• Mass of Hammer = 9 kg
• we know that, gravity = 9.8 m/s²

$\sf = > 9 \times 9.8$

$\sf = > 88.2$

$= > \bf88.2 \: kgm/ {s}^{2}$

We know that the unit of Force is Newton ( N )

• kgm/s² = N

so,

force applied by earth is 88.2 N

■ Weight :

Weight is the attractive force exerted by earth on an object . Weight of an object of mass m kg is F = mg. Here g= Acceleration due to gravity = 9.8 m/s²