Answer: Magnetic metals & non-magnetic metals both play an important role in engineering. Magnetism is the basis for many applications. At the same time, this property may also be unwanted in certain circumstances.
Therefore, it is important to know which metals are magnetic and which ones are not.
Explanation:
The period of a simple pendulum is given by:

where L is the pendulum length, and g is the gravitational acceleration of the planet. Re-arranging the formula, we get:

(1)
We already know the length of the pendulum, L=1.38 m, however we need to find its period of oscillation.
We know it makes N=441 oscillations in t=1090 s, therefore its frequency is

And its period is the reciprocal of its frequency:

So now we can use eq.(1) to find the gravitational acceleration of the planet:
Answer:
(B) 0.5 g
Explanation:
Newton's second law says ∑ F i = m a .
the rate of change in momentum of a body is proportional to the force applied on the body.
f∝ma
f=kma
were k is constant and equal to 1
The centripetal acceleration is an acceleration.
the tension on the swing and object weight goes to the left hand side while the centripetal acceleration goes to the right handside
At the bottom of the swing, ΣF = FT – mg = mac;
notice that the tension in the swing is 1.5 times the weight of the object
we can write
1.5mg – mg = mac,
0.5mg = mac
0.5 g=ac
Answer:
42.96 km/s
Explanation:
From the conservation of Energy

Mass gets cancelled

= Escape velocity of Earth = 11.2 km/s
= Velocity of projectile = 44.4 km/s

The velocity of the spacecraft when it is more than halfway to the star is 42.96 km/s