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block is released, it follows a bumpy path until it reaches a second spring. Throughout the path, there is a constant
frictional force of 4 N only on the surface of the hill but the horizontal sections are frictionless. The highest point of
the hill is 24 cm above the ground and the path length from point A to C is 90 cm in total (AB = BC = 45 cm).
a) Find the speed of the object at point B.
b) Find the speed of the object at point C.
c) Find the speed of the object when the 2nd spring (k2 = 250 N/m) is compressed by 15 cm.
A uniform horizontal beam 5.00 m long and weighing 3×10^2𝑁 is attached to a wall by a pin connection that allows the beam to rotate. Its far end is supported by a cable that makes an angle of 53 degrees with the horizontal. If a person weighing 6×10^2𝑁 stands 1.50 m from the wall, find the magnitude of the tension in the cable and the force 𝑅 exerted by the wall on the beam.
in collisions is a consequence of Newton’s third law of
motion.
A student is using a ‘Newton’s Cradle’. This consists of a set of identical solid metal balls hanging by threads from a frame so that they are in contact with each other.
He initially pulls one ball to the side. He releases the ball, it collides with the nearest stationary ball and stops. The ball furthest to the right immediately moves away. The middle three balls remain stationary.
(a) Explain what measurements the student would take and describe how he would use them to investigate whether momentum had been conserved in this event. [4]
(b) The student makes the following observations:
• the ball on the right returns and collides with a similar
result; this repeats itself a number of times
• after a while, the middle balls are also moving
• shortly afterwards, the balls all come to rest.
Discuss these observations in terms of energy
Mycobacteria move by ejecting slime from nozzles in
their bodies.
Explain the physics principles behind this form of propulsion.
