Review 1: Science Skills and Energy

Transcription

1 Name: Date: Blk: Review 1: Science Skills and 1. lthough there is no single right way to approach the scientific method, there are some general guidelines. a) Place the phrases on the right into the flowchart on the left in order to produce a logical sequence. Make Observations Formulate an Hypothesis Formulate an hypothesis Perform an Experiment Communicate the Results Make Observations nalyze Data and Draw Conclusions Hypothesis Rejected Hypothesis Not Rejected Hypothesis is Rejected Perform an Experiment nalyze Data & Draw Conclusions Communicate the Results Hypothesis is Not Rejected b) During their roller coaster build, Jaikar s group thought they noticed that as long as their starting height was the same, the length of time it took the marble to complete the track appeared to be the same regardless of the number of hills, loops or curves in their track. Satnam s group said they were wrong because adding hills, loops and curves to a track was bound to slow the marble down and take more time i) Write a hypothesis that addresses the observations and predictions above. If we build tracks starting at the same height but put in different number of loops and curves then the time it takes the marble will be the same. ii) Design an experiment to test your hypothesis. Include a procedure, your controls and your variables. Build 3 tracks, starting from the same height as follows: Track #: One loop and one hill Track #B: Two loops Track #C: Two hills Time how long it takes the marble to complete the tracks, three times on each track.

2 iii) Design a data table to record the data you will collect. Trial vg. Track B C 2. Perform the following metric conversions using dimensional analysis and write answer in scientific notation. a) hl = 8.7 dl b) µs = x 10-5 or ks hL x 100L x 10 dl = 8.7 dl 1 hl 1 L µs x 1 s x 1 ks µs 1000 s c) 912 cg = dag d) Mm = _1.01x10 7 or 10,100,000 mm 912 cg x 1 g x 1 dag = dag 100 cg 10 g Mm x m x 1000 mm 1 Mm 1m e) m = hm m x 1 hm_ 100 m f) mg= _6.45x 10-4 or _ cg mg x _ 1g x 100 cg 1000mg 1 g 3. Perform the following problems using dimensional analysis and write your answer in scientific notation. a) ron s mom just purchased an inflatable backyard pool that holds gallons of water. ron doesn t have a hose and must fill the pool using a 250 ml measuring cup. How many measuring cups full of water will ron need to use? (1 gallon = 3.79 L) ron s mom is mean! Does she not have a bucket? 2822 gallons x _3.79 L_ x 1000 ml = _1 cup = 42, cups 1 gallon 1 L 250 ml b) How many days would it take ron to fill the pool if it takes him 90s to go from his kitchen tap to the pool and back and he works night and day without stop? She makes him work all night too!?! 42, cups x 90 s x 1 h x 1 day = 44.6 days She s definitely breaking child labour laws. 1 cup 3600s 24 h

3 4. The Law of Conservation of states that cannot be created or destroyed. It can only change form. 5. a) Define the phrase energy transformation. change in energy from one form to another. b) What form of energy is always given off during any energy transformation? Thermal energy c) For each of the energy transformations below, give the input energy and its definition and the useful output energy and its definition. Device Input and Definition Output and Definition Chemical energy Motion stored in the bonds of chemical compounds. found in any set of moving parts Device Input and Definition Output and Definition Electrical energy Light found in moving electrons we can see 6. Potential energy comes from the position of an object. Kinetic energy comes from the _motion of an object. 7. The diagram below is a snapshot of a cart at some point in its journey. 4.0 Height of Cart (m) 1.5 C D 0.0 E a) If the total mechanical energy for the system is and the cart has a mass of 60 kg, complete the bar graphs below. Make sure to include numerical values for the energies as shown in graph.

4 C D 0 kj 0 kj 1.5 kj 0.9 kj KE PE ME KE PE ME KE PE ME b) t which point in the diagram above is the cart gaining KE? c) t which point in the diagram above is the cart gaining PE? _D d) Calculate the velocity of the cart at point and D J= ½ (60)v = 30v 2 30 = = vv 22 V = 8.9 m/s D 1500 J = ½ (60)v = 30v 2 30 = = vv 22 V = 7.07 m/s e) t what height will the PE of the system equal the KE of the system? at 2 m f) t what height will the cart be travelling at 4.0 m/s? KE= ½ (60) (4) = (60) (10) h KE = 480 J h = 1920 PE= 2400J 480 J 600 PE = 1920 J h = 3.2 m. Wile E. Coyote is probably best known for his falls of cliffs in his mad attempts to catch the road runner. Wile E. has a mass of 35 kg and was travelling at 10 m/s when he was half way down the cliff. a) What was Wile E. s KE half way down the cliff? KE = ½ (35) (10) 2 KE = 1750 J t halfway KE=PE b) What is Wile E. s KE just as he reaches the ground? 3500J c) What was his PE at the top of the cliff? 3500 J

5 d) How high was the cliff? 3500 = (35) (10) h h=10 m The cliff is 10 m high. e) If the roadrunner s mass is 10 kg, what is his PE at the top of the cliff? PE = (10) (10) (10) PE = 1000 J f) If the roadrunner also fell off the cliff, would he hit the ground with the same velocity as Wile E.? Road runner Wile E kj= ½ (10)v kj= ½ (35)v = v = v 2 V = 14.1 m/s V = 14.1 m/s