Answer:
Weight of the object will be 98 N
Explanation:
We have given mass of the object m = 10 kg
Acceleration due to gravity 
We have to find the weight of the object
Weight of the object is dependent on mass and acceleration due to gravity, it is the product of mass and acceleration due to gravity
So weight of the object W = mass × acceleration due to gravity
So 
So weight of the object will be 98 N
A machine can never be 100% efficient because some work is always lost
due to the lack of materials or equipment that would convert work by 100%. It follows
the second law of entropy. The ideal engine is known as Carnot’s engine having
a 100% efficiency. So far, no engine has ever gotten to 100%.
It would be D because there is more gravitational forces acting on it than a small block of wood
Let’s come back to the equation of SPEED OF AN ECHO
SPEED =2XDISTANCE/ TIME
So 337*7/2=1179.5 nearest meter =1800 m away
Hope you will get it right
Together the crust and upper mantle are called the lithosphere